# Source of radio emissions induced by the Galilean moons Io, Europa and
Ganymede: in situ measurements by Juno

###### Abstract

At Jupiter, part of the auroral radio emissions are induced by the Galilean
moons Io, Europa and Ganymede. Until now, except for Ganymede, they have been
only remotely detected, using ground–based radio–telescopes or electric
antennas aboard spacecraft. The polar trajectory of the Juno orbiter allows
the spacecraft to cross the range of magnetic flux tubes which sustain the
various Jupiter–satellite interactions, and in turn to sample in situ the
associated radio emission regions. In this study, we focus on the detection
and the characterization of radio sources associated with Io, Europa and
Ganymede. Using electric wave measurements or radio observations (Juno/Waves),
in situ electron measurements (Juno/JADE–E), and magnetic field measurements
(Juno/MAG) we demonstrate that the Cyclotron Maser Instability (CMI) driven by
a loss–cone electron distribution function is responsible for the encountered
radio sources. We confirmed that radio emissions are associated with Main
(MAW) or Reflected Alfvén Wing (RAW), but also show that for Europa and
Ganymede, induced radio emissions are associated with Transhemispheric
Electron Beam (TEB). For each traversed radio source, we determine the
latitudinal extension, the CMI–resonant electron energy, and the bandwidth of
the emission. We show that the presence of Alfvén perturbations and downward
field aligned currents are necessary for the radio emissions to be amplified.

JGR: Space Physics

School of Cosmic Physics, DIAS Dunsink Observatory, Dublin Institute for
Advanced Studies, Dublin 15, Ireland IRAP, Université de Toulouse, CNRS, CNES,
UPS, Toulouse, France LESIA, Observatoire de Paris, Université PSL, CNRS,
Sorbonne Université, Université de Paris, Meudon, France Pythéas, Aix
Marseille Université, CNRS, CNES, Marseille, France Laboratoire
d’Astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, Allée Geoffroy
Saint–Hilaire, 33615 Pessac, France CPHT, CNRS, Institut Polytechnique de
Paris, Route de Saclay, 91128 Palaiseau, France Department of Astrophysical
Sciences, Princeton University, Princeton, New Jersey, USA Aix–Marseille
Université, CNRS, CNES, Institut Origines, LAM, Marseille, France Technical
University of Denmark: Kgs. Lyngby, Denmark Department of Physics and
Astronomy, University of Iowa, Iowa City, Iowa, USA State Key Laboratory of
Space Weather, National Space Science Center, Chinese Academy of Sciences,
Beijing, China. College of Earth and Planetary Sciences, University of Chinese
Academy of Sciences, Beijing, China. Southwest Research Institute, San
Antonio, Texas, USA Department of Physics and Astronomy, University of Texas
at San Antonio, San Antonio, Texas, USA Space Research Corporation, Annapolis,
MD, USA 21403 NASA Goddard Space Flight Center, Greenbelt, MD, USA

C. K<EMAIL_ADDRESS>
All Jupiter–moon radio emissions are shown to be similarly triggered by the
CMI.

The crossed radio sources are colocated with either MAW, RAW or TEB
footprints.

The crossed radio sources coincide with downward field–aligned currents and
Alfvén perturbations.

##  1 Introduction

One of the main objectives of the Juno mission is to probe Jupiter’s auroral
regions in situ Bagenal . (2017) and, in particular, to search for the sources
of auroral radio emission. This is made possible by a suite of instruments
capable of acquiring high–quality plasma and wave measurements, such as Waves
Kurth . (2017), JADE–E <Jovian Auroral Distributions
Experiment–Electrons,¿[]2017SSRv..213..547M and MAG Connerney . (2017).
Imagers on–board Juno are also really useful to compare with auroral emissions
in other wavelengths, such as in ultraviolet with the UVS instrument
<Ultraviolet Spectrograph¿[]2017SSRv..213..447G.

These instruments provide measurements to study the radio wave amplification
process, and have already been able to locate the position of the sources Imai
. (2017, 2019); Louis . (2019a) and to confirm the Cyclotron Maser Instability
(CMI) as their underlying generation mechanism <¿[and see below for more
details]2017GeoRL..44.4439L, 2018GeoRL..45.9408L, 2017GeoRL..44.9225L,
2020GeoRL..4790021L, 2023_Collet_PRE9.

The Galilean moons Io, Europa and Ganymede are known to induce auroral
emissions, at radio Bigg (1964); Louis . (2017b); Zarka . (2017, 2018); Jácome
. (2022), ultraviolet <UV,¿[]1996Natur.379..323P, 1998…FGH767C,
2002Natur.415..997C and infrared Connerney . (1993); Mura . (2017, 2018)
wavelenghts . The motion of the moons across Jupiter’s magnetosphere in the
plasma torus surrounding them Szalay . (2022) generates an electric field,
inducing electric currents and/or Alfvén waves Goldreich Lynden-Bell (1969);
Neubauer (1980); Saur (2004) which both accelerate electrons along the
magnetic field lines in the moons’ flux tubes to kilo–electron–volts (keV)
energy. Note that the case of Callisto is not studied here, even if a
tentative detection of the Callisto UV footprint has been reported
Bhattacharyya . (2018), and hints of radio emissions have been observed to
this day using Galileo and Voyager data Menietti . (2001); Higgins (2007), and
not seen by Juno.

The Io, Europa, and Ganymede induced UV emissions are known to be produced by
downgoing electrons interacting with the Jovian neutral atmosphere. These
signatures are observed at the moons’ magnetic footprint and along their
tails, i.e the longitudinal extension of these spots in the downstream
direction relative to the plasma flow encountering the moon Bonfond . (2017a,
2017b). Recent in situ studies probed the magnetic field lines connected to
these UV footprints, and found that they are consistent with production by
Alfvénic interaction Szalay . (2018, 2020a, 2020b); Allegrini . (2020). On the
radio side, the moons’ induced emissions are believed to be produced by the
CMI and have already been simulated and well match the observations Hess .
(2008); Louis . (2017a, 2019b). This mechanism is also responsible for the
auroral radio emission (independent of the moons) and has been verified in
situ by ¡¿[involving loss–cone electron distribution functions, or
EDF]2017GeoRL..44.4439L, ¡¿[conics–type EDF]2018GeoRL..45.9408L and
¡¿[shell–type EDF]2023_Collet_PRE9. Recently, 2020GeoRL..4790021L showed with
in situ Juno measurements that the radio emission induced by the
Jupiter–Ganymede interaction is indeed produced by the CMI, from a loss
cone–type EDF, i.e., a lack in the up–going electron population, with a
characteristic energy of $4$–$15$ keV.

Since Jupiter–satellite radio and UV emissions are expected/assumed to be
colocated Hess . (2010), the question of the link between these emissions at
two different wavelengths naturally arises. In the Io case, we know that UV
and radio auroral emissions are produced by Alfvénic interactions, and that
the main and secondary radio emissions are respectively produced on the
magnetic field lines connected to the main Alfvén wing (MAW) and reflected
Alfvén wing (RAW) spots, and highly suspected for the Transhemispheric
Electron Beam (TEB) spots Hess . (2010); Lamy . (2022). But no simultaneous in
situ measurements have yet been analyzed. In the Ganymede case,
2020GeoRL..4790021L showed, extending the work of 2020GeoRL..4786527S, that
radio emission is produced above a magnetic flux tube mapping to a UV RAW
spot. 2022GeoRL..4996994H showed that radio emission seems to be produced
above the TEB spot. Finally in the Europa case, UV emissions have been
observed at the moon’s footprint and along the moon’s footprint tail Bonfond .
(2017a, 2017b); Allegrini . (2020); Hue . (2023); Rabia . (2023), but no
simultaneous observation of UV and radio emissions has yet been analyzed.

This study is a follow–up of the 2020GeoRL..4790021L analysis, focusing on the
three known types of Jupiter–satellite radio emissions. In Section 2, we
briefly recall the theory of the Cyclotron Maser Instability. In Section 3, we
present the observations of Jupiter–Io (J–I), –Europa (J–E) and –Ganymede
(J–G) radio emission source crossings and calculate the CMI growth rate
(whenever possible) and determine the emission parameters. Finally, in Section
4, we summarize and discuss the results.

##  2 The Cyclotron Maser Instability

The CMI is known to be responsible for the production of auroral radio
emission of Earth, Saturn and Jupiter Wu Lee (1979); Le Queau . (19841,
19842); Wu (1985); Pritchett (1986); Treumann (2006); Mutel . (2010); Lamy .
(2010); Kurth . (2011); Louarn . (2017, 2018).

In a tenuous and magnetized enough plasma, i.e., wherever the electron plasma
frequency $f_{\text{pe}}$ is much lower than the electron cyclotron frequency
$f_{\text{ce}}$, and with weakly out–of–equilibrium/non–maxwellian
relativistic electrons, the CMI can directly amplify X–mode waves at a
frequency close to the electron cyclotron frequency $f_{\text{ce}}$, along the
surface of a hollow cone. The CMI is a wave–electron instability for which the
resonance condition is reached when the Doppler–shifted angular frequency of
the wave in the frame of the electrons ($\omega-k_{||}v_{r_{||}}$) is equal to
the relativistic gyration frequency of resonant electrons
($\omega_{ce}\Gamma_{r}^{-1}$):

$\omega=\omega_{ce}\sqrt{1-\frac{v_{r}^{2}}{c^{2}}}+k_{||}v_{r_{||}}~{}~{}~{}~{},$
(1)

with k the wave vector and $v_{r}$ the velocity of the resonant particle, and
$\Gamma_{r}^{-1}=\sqrt{1-v_{r}^{2}/c^{2}}$ the relativistic Lorentz factor.
The ⟂ and || indices represent the perpendicular and parallel components of
the wave vectork or the velocity $v_{r}$ with respect to the magnetic field
$B$.

In the weakly relativistic case ($v_{r}\ll c$), the above resonance condition
can be rewritten as the equation for a resonant circle in the [$v_{\perp}$,
$v_{||}$] velocity space:

$v_{\perp}^{2}+(v_{||}-v_{0})^{2}=v_{r}^{2}~{}~{}~{}~{},$ (2)

defined by its center:

$v_{0}=\frac{k_{||}c^{2}}{\omega_{ce}}~{}~{}~{}~{},$ (3)

and its radius

$v_{r}=\sqrt{v_{0}^{2}-2c^{2}\Delta\omega}~{}~{}~{}~{},$ (4)

with

$\Delta\omega=(\omega-\omega_{ce})/\omega_{ce}$ (5)

the frequency shift between the emission frequency and the cyclotron electron
frequency.

For the CMI to amplify radio emission, the electron distribution function
needs to present a positive $\partial f/\partial v_{\perp}$ gradient along the
resonant circle in the velocity space, and radio waves will be amplified if
positive growth rates are presents.

The simplified version of the growth rate expression used by
2017GeoRL..44.4439L, 2018GeoRL..45.9408L, 2020GeoRL..4790021L is well adapted
to the amplification of X–mode waves propagating at frequencies close to
$f_{ce}$, for a refraction index $N=1$ and a moderately energetic ($E\ll 511$
keV) and low–density ($f_{pe}\ll f_{ce}$) plasma. But this expression contains
an approximation at low pitch angle, and therefore applies only to growth rate
calculation in the loss cone. Therefore to generalize the calculation of
growth rate in the whole electron distribution function, we use the expression
of 2023_Collet_PRE9, derived from the dispersion relation in X mode from
1984JGR….89.2831L <see Annexe A of¿[for the full demonstration of the growth
rate expression]2023_Collet_PRE9. They assumed that the plasma is composed of
one cold population at thermodynamic equilibrium and one non–thermal energetic
(or hot) population. In this study, the hot electron density is the one
measured by JADE–E for electrons above $1$ keV energy.

$\gamma=\frac{(\frac{\pi}{2}\epsilon_{h})^{2}}{1+(\frac{\epsilon_{c}}{2\Delta\omega})^{2}}c^{2}\int_{0}^{\pi}d\theta
v_{r}^{2}\sin^{2}(\theta)\frac{\partial f_{h}}{\partial
v_{\perp}}(v_{0}+v_{r}\cos(\theta),v_{r}\sin(\theta))$ (6)

In this equation, $\epsilon_{\alpha}=\omega_{p\alpha}/\omega_{\mathrm{ce}}$,
where $\omega_{p\alpha}$ is the plasma frequency of the hot
($\alpha=\mathrm{h}$) or cold ($\alpha=\mathrm{c}$) electrons. $f_{h}$ is the
normalized electron distribution function of hot electrons ($\int fdv^{3}=1$).
In practice, the factor to normalize the distribution function is
$c^{3}10^{-18}/n_{e}$, where $n_{e}$ is the electron density (in cm-3).

Equation 6 means that the growth rate is obtained by integrating $\partial
f_{h}/\partial v_{\perp}$ along a resonant circle in the normalized velocity
space [$v_{||}$,$v_{\perp}$], defined by its center $v_{0}$ (Equation 3), its
radius $v_{r}$ (Equation 4) and the angle $\phi\subseteq$[$0$–$\pi$] along
this circle.

By calculating and maximizing the growth rate, we are able to assess the most
CMI–unstable electron population and characterize the resulting amplified
waves, and then obtain the characteristics of the emission (e.g., the energy
of the resonant electrons and the aperture of the beaming angle).

One of the 3 anodes of JADE–E is unfortunately not functional. As a result,
due to Juno’s spin and its orientation with respect to the magnetic field
lines, it sometimes happens that certain pitch angles are not sampled. In
order to calculate the growth rate of the wave along the different resonance
circles in velocity space, JADE–E needs to sample sufficient pitch angles. If
too much of the EDF measurement is missing ($60$% along a resonant circle), we
cannot calculate the growth rate and determine the characteristics.

However, assuming that Juno is located within the radio source region (if the
radio emission is observed very close to, or even below, $f_{ce}$), we are
still able to obtain some information about the source size and the
characteristics of the emission, by measuring the emission frequency observed
by Juno/Waves data. If the EDF is of shell type, i.e. if $f\leq
f_{\mathrm{ce}}$, then the resonant circle is centered on $v_{0}=0$, therefore
$k_{||}=0$ (see Equation 3), and Equation 1 can then be rewritten as:

$\omega_{shell}=\omega_{ce}\sqrt{1-\frac{v_{r}^{2}}{c^{2}}}~{}~{}~{}~{}.$ (7)

Thus, from the measurements of the local electron cyclotron frequency
($\omega_{ce}=2\pi f_{ce}$) and the emission frequency $f_{\mathrm{shell}}$,
and using $E=0.5\times m_{e}v^{2}$ (with $m_{e}=511$ keV$/\text{c}^{2}$ the
electron mass), the electron energy in keV in the shell–driven CMI case can be
written as:

$E\simeq
255.5\times\left(1-\left(\frac{f_{\mathrm{shell}}}{f_{\mathrm{ce}}}\right)^{2}\right)~{}~{}~{}~{}.$
(8)

In the case of a loss–cone (lc) type EDF, i.e. if $f>f_{\mathrm{ce}}$, in the
weakly relativistic case ($v_{r}\ll c$) the resonant equation can be rewritten
as <for more details see Equations 2–12 of¿[]2019A&A…627A..30L:

$\omega_{lc}\simeq\frac{\omega_{ce}}{\sqrt{1-\frac{v_{r}^{2}}{c^{2}}}}~{}~{}~{}~{},$
(9)

and therefore the electron energy in keV in the loss cone–driven CMI case can
be written as:

$E\simeq
255.5\times\left(1-\left(\frac{f_{ce}}{f_{\mathrm{lc}}}\right)^{2}\right)$
(10)

##  3 Observations and Analysis of Radio Emission Sources Crossings

Due to the large extension of Io’s tail Szalay . (2020b) and to Juno’s polar
orbit, the spacecraft crossed Io’s magnetic flux tubes at least twice every
orbit (North, then South). However, electron fluxes connected to Io’s UV
aurora are not observed in appreciable or detectable amounts by Juno/JADE–E
every transit of these flux tubes. Therefore, during the first 26 Juno
perijoves, 18 cases of electron fluxes connected to Io’s magnetic flux tube
have been reported using the JADE–E measurements Szalay . (2020b). By studying
the data from perijoves (PJ) #$27$ to #$31$, we report five more cases of Io’s
tail flux tube crossing where electron fluxes were measured. In the Europa
case, electron fluxes connected to Europa’s UV aurora were measured ten times
Allegrini . (2020); Rabia . (2023). Finally, electron flux connected to
Ganymede’s UV aurora were measured only two times. The first one during PJ
#$20$ <reported by¿[]2020GeoRL..4786527S, 2020GeoRL..4790021L and the second
one during PJ #$30$ <studied in details by¿2022GeoRL..4996994H.

For all moon’s flux tube crossings detected by JADE–E, we investigate Waves
observations to look for radio emission located below $1$ % the local electron
cyclotron frequency $f_{\mathrm{ce}}$ (determined from the local magnetic
field amplitude measured by the MAG instrument). We therefore considered these
cases as a potential crossing of a radio source. We then study the EDF
obtained from JADE–E. 2020GeoRL..4786527S, 2020GeoRL..4789267S,
2020GeoRL..4789732A, 2023RabiaGRL studied the downward electrons and the
production of UV emissions linked to these downward electron currents, as well
as the presence of Alfvénic current systems capable of accelerating these
electrons. We study here the CMI–unstability of measured EDF, in the
continuity of 2020GeoRL..4790021L. To go further than 2020GeoRL..4790021L, we
study instability in the whole EDF, to search not only for loss–cone type
instabilities, but also shell type. We also study the upward and downward
electrons, as well as the magnetic field perturbation, to determine the
presence of field aligned currents (FAC) using 2021JGRA..12629469W,
2022JGRA..12730586A method and Alfvén perturbations capable of accelerating
electrons.

Downtail distances with respect to the main spot were recently revised using
Juno/UVS data. Over 1,600 spectral images of the Io, Europa, and Ganymede UV
footprint were analyzed to provide statistical positions of the main Alfvén
wing spots. This allowed 2023JGRA..12831363H to estimate the distance from
Juno to the main spot at the time of the source crossings that will be
described in this Section, as well as derived observationally an estimation of
the Alfvén travel time for each three moons. Note that the actual position of
the main Alfvén wing spots is affected by the background magnetospheric
conditions (density of the plasma sheet along the field line connected to the
satellite footprint and/or magnetic field strength), and therefore shifts of
the main Alfvén wing spots mapped to the equatorial region up to $\pm 2^{o}$
(Io), $\pm 4^{o}$ (Europa) and $\pm 5^{o}$ (Ganymede) are not unusual
<See¿[Figures 4, 5, 7]2023JGRA..12831363H. A negative distance to the main
spot therefore translate either (i) a source crossing associated with a
transhemispheric electron beam located much upstream of the Alfvén wing spots,
or (ii) a change in the plasma condition (e.g., lower plasmasheet density
and/or higher magnetic field magnitude).

###  3.1 Jupiter–Io radio emission source crossings

Out of the 23 cases where electron fluxes connected to Io’s tail flux tube
were measured, simultaneous radio emissions below $1.01\times f_{\mathrm{ce}}$
were observed in only 4 cases. Figure 1 displays Juno measurements around an
Io flux tube encounter, during PJ#5 on 2017–03–27 (2017 March 27th) in the
Southern hemisphere <already reported by¿[]2019GeoRL..4611606L. Panel (A)
presents the Juno/Waves measurements <in low–resolution
mode,¿[]2017SSRv..213..347K around the perijove (from $\sim-1.5$ h before to
$\sim 2.5$ h after). Panel (B) is a $5$ min zoom–in of panel (A) using
Juno/Waves high–resolution mode. The decreasing solid–black and dashed–black
lines in panels (A,B) represent respectively the electron cyclotron frequency
$f_{ce}$ and $1.01\times f_{ce}$. Panels (C)–(E) show the Juno/JADE–E
measurements of (C) the electron differential number flux (or intensity), (D)
the electron distribution function of upgoing electrons and (E) the partial
electron density (where all the energy population $<0.1$ keV is not accounted
for). Figure 1F displays the FAC calculated based on 2022JGRA..12730586A’s
method (see sections 1.3 and 2 of their SI for more details). This method used
the residual magnetic field perturbation $\delta B$, defined as the difference
between the Juno/MAG magnetic field measurements and the magnetic field values
obtain from the combination of the 2018GeoRL..45.2590C magnetic field and
1981JGR….86.8370C current sheet models. The FAC are then calculated from the
residual magnetic field perturbation in the azimuthal direction ($\delta
B_{\phi}$).

Figure 1: Caption on next page

Juno data during Perijove 5, on 27 March 2017. Panels (A,B) display Juno/Waves
data (A) in low–resolution mode and (B) in high–resolution mode. The
solid–black lines represent the electron cyclotron frequency derived from the
magnetic field measurements of Juno/MAG, and the dashed–black line is
$1.01\times f_{\text{ce}}$. Panels (C–D) display Juno/JADE–E measurements: (C)
the electron differential number flux (or intensity) of all electrons; (D) the
electron distribution function for energy in range [2–21] keV as a function of
pitch angles; Panels (E) displays the normalized growth rate
$\gamma/\omega_{\mathrm{ce}}$ maximal value calculated using Equation 6. Panel
(F) shows the partial electron density calculated from the JADE–E flux. Panel
(G) shows the field aligned currents calculated based on 2022JGRA..12730586A’s
method, using magnetic field fluctuations in the azimuthal direction ($\delta
B_{\phi}$) deduced from the Juno/MAG measurements. The vertical dashed black
lines represent the flux tube crossing as inferred from JADE data, while
vertical dashed red lines represent the time interval where positive growth
rate are calculated from JADE–E measurements. Panel (H) displays a UV map of
the southern hemisphere, using Juno/UVS measurements from 09:35:49 to
09:55:20. The red line indicates Juno’s trajectory, with the red dots its
position at the start and end time of the measurements used for this image. Io
UV footprint is highlighted by the red ellipse.

Figure 1B displays an emission very close to $1.01\times f_{ce}$, while we
observe an enhancement in the electron energy flux (panel C) at a few keV, a
strong intensification in the distribution function (panel D), an increase of
the electron density (panel F) and a clear upward current surrounded by
downward FAC (panel G). Figure S1 in Supporting Information displays the
magnetic field fluctuations for all the magnetic field components in spherical
coordinates. The magnetic field perturbation associated to the FAC shows clear
fluctuations in the transverse component (perpendicular to B, corresponding to
$\delta B_{\phi}$ and $\delta B_{\theta}$) while no fluctuations are observed
in the radial component ($\delta B_{r}$). The fluctuations are therefore
confined to the transverse components, which is indicative of a lack of
horizontal current, and therefore indicative of FAC (displayed Figure 1F).
Moreover, no fluctuations are seen in the total magnetic field magnitude
$\delta|B|$, indicating that these variations are Alfvénic in nature Gershman
. (2019); Kotsiaros . (2019).

Figure 2: Caption on next page

Panels (A,B): electron distribution function in the velocity space [$v_{||}$,
$v_{\perp}$] measured by JADE–E on 2017–03–27 at (A) 09:30:52 (inside the Io
tail radio source) and (B) 09:31:00 (outside the Io tail radio source). In
that case, the $v_{||}<0$ part of the EDF represents upgoing electrons, while
$v_{||}>0$ represents downward electrons. The colorbar and the isocontours are
shown using a logarithmic scale in units of $s^{3}.km^{-6}$. The radial red
thick line indicates the theoretical loss cone value. The blue circular
half–circle in panel (A) display the resonant circle with the highest growth
rate. Panels (C,D): Normalized growth rate ($\gamma/\omega_{ce}$) estimates
for different resonant circles at different centers $v_{0}$ and radii $v_{r}$.
Panels (E,F): Normalized growth rate as a function of the frequency shift
$\Delta\omega$ between the emission frequency and the cyclotron electron
frequency (see Equation 11 for all resonant circle with positive growth rate
$\gamma$. Blue circles represent growth rate for resonant circles tangential
to the theoretical value of the loss cone. Orange stars represent growth rate
growth rate for resonant circle inside the theoretical loss cone. Both are
considered as loss–cone type instabilities. Green diamonds represent growth
rate for resonant circles of shell-type.

Figures 2A–B display the electron distribution function in the velocity space
measured by Juno/JADE–E at (A) 09:30:52 and (B) 09:31:00. From these data and
Equation 6 we can calculate the normalized growth rate of the emission along
different resonant circles to determine the unstable electron population.
Figures 2C–D show the estimated normalized growth rate $\gamma/\omega_{ce}$
along resonant circles in the whole EDF, calculated for different centers
(x–axis) and different radii (y–axis). Figures 2E–F displays the growth rate
$\gamma$ as a function $\Delta\omega$ for each resonant circle displaying a
positive growth rate.

Positive growth rates are obtained for the EDF of Figure 2A, and not for the
EDF of Figure 2B. Only resonant circles inside the theoretical loss cone show
positive growth rate (blue circles and orange stars in Figure 2E), while no
positive growth rate are found for shell–type resonant circles (green
diamonds). By doing this calculation before, during and after the crossing of
the Io’s tail flux tube (see Figure 1E), we are able to determine when Juno is
in the source, and thus determine its size and the characteristics of the
emission. In this case, positive growth rate are obtained along loss–cone type
resonant circles from 09:30:51 to 09:30:59 ($\pm 1$ sec). This time interval
is indicated in Figure 1 by the two vertical dashed red lines. Juno’s velocity
being $\sim 45$ km/s during this time, we determined that the source size is
$360\pm 45$ km. From the growth rate calculation, we can determine that the
energy of the resonant electrons responsible for this emission is in the range
[$1$–$15$] keV, with an opening angle $\theta$ of the beaming cone in the
range [$74\mathrm{\SIUnitSymbolDegree}$–$85\mathrm{\SIUnitSymbolDegree}$]. To
determine this value, we used Equation 7 of 2020GeoRL..4790021L:

$\theta=\text{acos}(\beta_{0}/(1+\Delta\omega))~{}~{}~{}~{},$ (11)

based on the assumptions of Section 2.

It is interesting to note that enhanced electron fluxes are observed for the
period of 09:30:51 to 09:31:02 <determined as the flux tube
crossing,¿[]2020GeoRL..4789267S, while the J–I radio source is only crossed
from 09:30:51 to 09:30:59 (determined from the growth rate calculation), which
corresponds to the time where Juno is inside a downward current (corresponding
to upward electrons). When Juno is located inside an upward current (i.e.,
downward electrons), no positive growth rate are obtained.

The same method is applied to the data from PJ#6 (North) on 2017–05–19, during
which a J–I radio source is crossed between 05:39:31 and 05:39:39 (see Figure
S2), and to PJ#29 (North) on 2020–09–16 during which a J–I radio source is
crossed between 02:00:34 and 02:00:36 (see Figure S3). For the crossing of the
J–I radio source that occurs in the northern hemisphere during PJ#5 on
2017–03–26 around 08:34:40 (see Figure S4), we do not have JADE–E measurements
of the upgoing electrons, and we therefore can not calculate the growth rate.
Since no radio emission is observed below $f_{ce}$, we therefore assume that
loss–cone EDF remain the prominent source of free energy for the CMI, and we
therefore use Equation 10 to determine the electron energy. The results for
these three crossings, i.e., radio source size, resonant electron energy,
$\text{f}_{\text{emission}}$ and opening angle of the beaming cone, are
summarized Table 1.

As for PJ#5 (South), FAC and Alfvénic perturbations are observed during PJ#5
(North) and PJ#29 (North) Io’s flux tube crossing (see Figures S4 and S3,
respectively), with perturbations in the transverse components of the magnetic
field ($\delta B_{\phi}$ and $\delta B_{\theta}$) while no perturbation is
observed in the radial ($\delta B_{r}$) and compressive ($\delta|B|$)
components. Furthermore, as for PJ#5 (South), the radio source is not crossed
anywhere inside Io’s flux tube, but only when Juno is located inside a
downward current (i.e., upward electrons). During PJ#6 (North), nothing is
observed in the magnetic field perturbations, which could be due to the fact
that the electron density is very low ($<1$ cm-1), which could induce a
perturbation too weak for the MAG instrument to detect.

Based on the recalculation of the downtail distance to the main spot of Io
$\Delta\lambda_{\mathrm{Alfv\acute{e}n}}$ Hue . (2023), the J–I radio emission
source crossings of PJ#5 North, PJ#5 South, PJ#6 South are all associated with
a Reflected Aflvén Wing (RAW) spot downtail of Io. The intensity of the radio
emission seems to be quite similar for crossings occurring close to the main
spot, with an intensity of $2$–$3\times 10^{-6}$ $V^{2}.m^{-2}.Hz^{-1}$ when
$3.3^{\mathrm{o}}<\Delta\lambda_{\mathrm{Alfv\acute{e}n}}<10.8^{\mathrm{o}}$.
The intensity seems to be lower when $\Delta\lambda_{\mathrm{Alfv\acute{e}n}}$
is large, with an intensity of $8\times 10^{-8}$ $V^{2}.m^{-2}.Hz^{-1}$ for
$\Delta\lambda_{\mathrm{Alfv\acute{e}n}}=87.4^{\mathrm{o}}$.

###  3.2 Jupiter–Europa radio emission

During the 26 first perijoves, enhanced electron fluxes connected to Europa’s
UV aurora were measured ten times Allegrini . (2020); Rabia . (2023). A radio
source was crossed only during PJ#12 on the Northern hemisphere, on 2018–04–01
around 08:15:44.

Figure 3: Panels (A,B) display Juno/Waves data (A) in low–resolution mode and
(B) in high–resolution mode. The solid–black lines represent the electron
cyclotron frequency derived from the magnetic field measurements of Juno/MAG,
and the dashed–black line is $1.01\times f_{\text{ce}}$. Panels (C–E) display
Juno/JADE–E measurements: (C) the electron differential number flux (or
intensity) of all electrons; (D) the electron distribution function for energy
in range [2–21] keV only for pitch angles
[$0\mathrm{\SIUnitSymbolDegree}$–$60\mathrm{\SIUnitSymbolDegree}$]
corresponding to up–going electrons; (E) partial electron density calculated
from the JADE–E flux. Panel (F) displays a UV map of the northern hemisphere,
using Juno/UVS measurements from 08:50:24 to 09:10:20. The red line indicates
Juno’s trajectory, with the red dots its position at the start and end time of
the measurements used for this image. Europa UV footprint is highlighted by
the red ellipse.

Figure 3 displays Juno/Waves (panels A–B), Juno/JADE–E measurements (panels
C–E) and Juno/UVS (panel F) during the crossing of flux tube connected to a
Europa’s downtail UV footprint Allegrini . (2020). During the time of the flux
tube crossing, determined by the enhancement of the electron flux in JADE–E
measurements (Figures 3C–D), a radio emission is observed below $1.01\times
f_{ce}$ (Figure 3B). However, the JADE–E instruments did not record data of
upgoing electrons in the loss cone during this time. We therefore cannot
calculate the loss–cone or shell CMI growth rate for this EDF. Since no radio
emission is observed below $f_{\mathrm{ce}}$, we therefore assume that
loss–cone EDF remain the prominent source of free energy for the CMI. We then
apply Equation 10 to estimate the energy of the resonant electron. Looking at
the Juno/Waves measurements (Figure 3B), we determine that the radio emission
observed during Europa’s flux tube crossing is emitted at a frequency between
0.7 and 1.5% above the electron cyclotron frequency $f_{ce}$ (solid dark
line). This frequency measurement leads to an energy of the resonant electrons
in the range [$3$–$8$] keV, and an opening angle of the beaming cone in the
range [$79\mathrm{\SIUnitSymbolDegree}$–$84\mathrm{\SIUnitSymbolDegree}$].

The MAG measurements of the magnetic field perturbation show no strong
variation of the different components. Once again, as in the case of PJ#6N for
Io, the electron density is very low ($\sim 2$ cm-1) which could induce
perturbations too weak and/or too short for the MAG instrument to detect.

Based on the latest work of 2023RabiaGRL and the recalculation of
$\Delta\lambda_{\mathrm{Alfv\acute{e}n}}$ Hue . (2023), we can conclude that
the J–E radio source crossed during PJ#12 is associated with a
Transhemispheric Electron Beam (TEB) spot uptail of the main Europa UV spot.

###  3.3 Jupiter–Ganymede radio emission

So far, flux tubes connected to Ganymede footprint tail aurora have been
crossed twice: the first one during PJ #$20$ on 2019–05–19 between 07:37:14
and 07:37:32 <reported by¿[]2020GeoRL..4786527S, 2020GeoRL..4790021L and the
second one during PJ #$30$, on 2020–11–08 around 02:55:02 Hue . (2022).

We already reported the PJ#20N crossing in 2020GeoRL..4790021L, but at that
time, we did not look at the Juno/MAG measurements, which was done by
2020GeoRL..4786527S (and plotted in Figure S5). During this Ganymede footprint
tail aurora flux tube crossing, fluctuations in the transverse components
($\delta B_{\phi}$ and $\delta B_{\theta})$ were observed, while no
fluctuations were measured in the radial ($\delta B_{r}$) and compressive
($\delta|B|$) components, which indicates the presence of field aligned
currents and Alfvénic perturbations. As for the J–I radio emission sources, it
should be noted that the radio source is only crossed when Juno is in a
downward current (i.e., upward electrons). Based on 2020GeoRL..4786527S,
2020GeoRL..4790021L, this radio emissions is associated with a RAW UV spot
(with a
$\Delta\lambda_{\mathrm{Alfv\acute{e}n}}=8\mathrm{\SIUnitSymbolDegree}$).
However, based on the recent work of 2023JGRA..12831363H, for this J–G radio
source,
$\Delta\lambda_{\mathrm{Alfv\acute{e}n}}=-1.8\mathrm{\SIUnitSymbolDegree}$.
Therefore, due to the error of $\textpm 5\mathrm{\SIUnitSymbolDegree}$ on the
position of the MAW for Ganymede (due to possible change in the in situ plasma
condition, see penultimate paragraph of Section 1), it appears that the J–G
radio source crossed during PJ#20, is connected not to the RAW spot, but to
the MAW spot.

Concerning the second case, during PJ#30 on 2020–11–08 (northern hemisphere),
Ganymede footprint tail aurora flux tube was crossed around 02:55:02, with
radio emission tangent to $1.01\times f_{ce}$ at the same time
<see¿[]2022GeoRL..4996994H. Unfortunately, JADE–E did not measure the upward
electrons during Ganymede flux tube crossing. Therefore, we can only estimate
the electron energy using Equation 10 (as no radio emission is observed below
$f_{ce}$). Around 02:55:02, Waves measured a radio emission between $1.804$
MHz and $1.894$ MHz. Based on the Juno/MAG measurements of the magnetic field
amplitude, $f_{ce}=1.7857$ MHz. These values of the emission frequency lead to
an estimation of the resonant electron energy in the range [$5.1$–$28.5$] keV,
and an aperture angle of the beaming cone in the range
[$70\mathrm{\SIUnitSymbolDegree}$–$81\mathrm{\SIUnitSymbolDegree}$], provided
that Juno actually flew through the radio source. During the crossing, MAG
measurements show a $\sim 10$ nT perturbation in $\delta B_{\phi}$, while no
perturbation is observed in the radial $\delta B_{r}$ and compressive
$\delta|B|$ components, which indicates again the presence of Alfvénic
perturbations and field aligned currents, with an upward current equatorward
of a downward current.

Based on the work of 2022GeoRL..4996994H, we can also conclude that the J–G
radio emission source crossed during PJ#30 is associated with a
Transhemispheric Electron Beam (TEB) spot uptail of the main Europa UV spot.

The results for these two J–G radio source crossings are summarized in Table
1.

##  4 Summary and Discussion

Table 1: Results for the Jupiter–Io, Jupiter–Europa and Jupiter–Ganymede radio
emissions source crossings. Is given for each crossing: the name of the moon;
the hemisphere of the emission; the associated perijoves; the date and time
interval of the radio source crossing as inferred from growth rate calculation
when JADE data were available; the JADE data availability; the minimal
frequency reached by the radio emission (in MHz); the frequency bandwidth of
the emission (in percentage above $f_{\mathrm{ce}}$); the maximum intensity
(in V2.m-2.Hz-1) of the emission; the electron energy (in keV); the opening
half–angle of the beaming cone (in $\mathrm{\SIUnitSymbolDegree}$); the radio
source size (in km); the downtail distance to the Main Alfvén Wing spot
$\Delta\lambda_{\mathrm{Alfv\acute{e}n}}$ Hue . (2023); the associated UV
emission at the footprint of the magnetic field line associated to the source
(MAW: Main Alfvén Wing: RAW: Reflected Alfvén Wing; TEB: Transhemispheric
Electron Beam).

Moon Io Io Io Io Europa Ganymede Ganymede Hemisphere South North North North
North North South Perijove PJ5 PJ5 PJ6 PJ29 PJ12 PJ20 PJ30 Date
(Year–Month–Day) 2017–03–27 2017–03–27 2017–05–19 2020–09–16 2018–04–01
2019–05–29 2020–11–08 Time interval (HH:MM:SS) 09:30:51–59 around 08:34:40
05:39:31–39 02:00:34–36 around 09:15:44 07:37:25–30 around 02:55:02 JADE data
Yes No Yes Yes No Yes No $f_{\mathrm{min}}$ (MHz) $4.7$ $20.8$ $12.8$ $27.7$
$6.7$ $6.5$ $1.8$ $f_{\text{emission}}$ (% $>f_{ce}$) $3$–$18\times 10^{-3}$
$3$–$29\times 10^{-3}$ $2$–$14\times 10^{-3}$ $5$–$40\times 10^{-3}$
$7$–$15\times 10^{-3}$ $5$–$21\times 10^{-3}$ $5$–$40\times 10^{-3}$ Intensity
max. (V2.m-2.Hz-1) $3\times 10^{-6}$ $3\times 10^{-6}$ $8\times 10^{-8}$
$2\times 10^{-6}$ $1\times 10^{-7}$ $1\times 10^{-6}$ $3.5\times 10^{-9}$
Electron energy (keV) $1$–$15$ $2$–$20$ $1$–$5$ $3$–$10$ $3$–$8$ $4$–$15$
$2$–$20$ Opening angle $74$–$85\mathrm{\SIUnitSymbolDegree}$
$74$–$85\mathrm{\SIUnitSymbolDegree}$ $77$–$86\mathrm{\SIUnitSymbolDegree}$
$73$–$84\mathrm{\SIUnitSymbolDegree}$ $79$–$84\mathrm{\SIUnitSymbolDegree}$
$76$–$83\mathrm{\SIUnitSymbolDegree}$ $74$–$85\mathrm{\SIUnitSymbolDegree}$
Radio source size (km) $360\pm 45$ $500\pm 100$ $415\pm 50$ $250\pm 50$
$200\pm 49$ $250\pm 50$ $75\pm 50$ $\Delta\lambda_{\mathrm{Alfv\acute{e}n}}$
(o) $3.3^{\mathrm{o}}$ $10.8^{\mathrm{o}}$ $87.4^{\mathrm{o}}$
$7.8^{\mathrm{o}}$ $-10.5^{\mathrm{o}}$ $-1.8^{\mathrm{o}}$ $-7^{\mathrm{o}}$
Associated UV emission RAW RAW RAW RAW TEB MAW TEB

Concerning the characteristics of the radio emission, the results are similar
for the three Galilean moons Io, Europa and Ganymede, in terms of driving
mechanism (CMI), electron energy, and beaming. The in situ measurements by
JADE–E show that the radio emission is triggered by the Cyclotron Maser
Instability, driven by a loss–cone electron distribution function. No unstable
shell–type electron distribution function are detected in JADE–E measurements.
The energy of the resonant electrons is in the range [$1$–$20$] keV, and the
half–opening cone angle is in the range
[$74\mathrm{\SIUnitSymbolDegree}$–$86\mathrm{\SIUnitSymbolDegree}$].

These values are in agreement with those recently obtained using ground–based
radio observation, such as the Nançay Decameter Array or NenuFAR, such as the
recent work of 2022JGRA..12730160L who determined for Io an opening angle
$\theta(f)$ in the range
[$70\mathrm{\SIUnitSymbolDegree}$–$80\mathrm{\SIUnitSymbolDegree}$] and
electron energies in the range [$3$–$16$] keV. For Europa, 2023PREIX_Lamy
measured on an unique detection an opening angle in the range $\theta$ =
[$80\mathrm{\SIUnitSymbolDegree}$–$86\mathrm{\SIUnitSymbolDegree}$] and an
electron energy in the range [$0.5$–$3$] keV. For Ganymede, the observations
of three emissions lead them to a determination of a beaming angle in the
range $\theta$ =
[$71\mathrm{\SIUnitSymbolDegree}$–$87\mathrm{\SIUnitSymbolDegree}$] and an
electron energy in the range [$0.5$–$15$] keV

The radio sources have a latitudinal extent of a few hundreds of kilometers.
In the cases where we are able to constrain the radio source location
(provided that we have JADE–E measurement of the up–going electrons), the
sources were not crossed anywhere in the flux tube, but only in the downward
Field Aligned Currents.

Based on the previous works of 2020GeoRL..4786527S, 2020GeoRL..4789267S,
2020GeoRL..4790021L, 2022GeoRL..4996994H, 2023RabiaGRL and the recalculated
downtail distances from the UV moon main spot using 2023JGRA..12831363H, we
also concluded that in the case of Io, all radio source crossed were
associated with a RAW UV spot. These crossed radio sources are therefore
associated with the secondary radio emissions observed in the usual dynamic
spectrum.

In the case of Europa, the only case of radio emission source so far is
associated with a TEB spot. Finally, for Ganymede, one radio source is
associated with a MAW spot, while the second one is associated with a TEB
spot. Even if we didn’t detect any radio emission above TEB for Io, these
results are is in agreement with the interpretation of the first
identification of some Io–DAM linked to the TEB spot analyzed in
2022JGRA..12730160L.

The maximal intensity is quite similar between all cases close to the main UV
spot, with a value of $2$–$3\times 10^{-6}$ $V^{2}.m^{-2}.Hz^{-1}$ in a
interval
$3.3^{\mathrm{o}}<\Delta\lambda_{\mathrm{Alfv\acute{e}n}}<10.8^{\mathrm{o}}$,
with a decrease of the intensity with long distance downtail ($8\times
10^{-8}$ $V^{2}.m^{-2}.Hz^{-1}$ for the case at
$\Delta\lambda_{\mathrm{Alfv\acute{e}n}}=87.4^{\mathrm{o}}$). But with only
one case very far downtail, we can’t produce a fit of this decrease as a
function of $\Delta\lambda_{\mathrm{Alfv\acute{e}n}}$. However, the maximal
intensity of the emission is quite smaller for the radio source crossed above
a TEB spot ($10^{-9}$–$10^{-7}$ $V^{2}.m^{-2}.Hz^{-1}$). This could be related
to the type of electron distribution, which seems different near tail
(non–monotonic) than far tail (broadband), at least for Europa with a
separation at $\Delta\lambda_{\mathrm{Alfv\acute{e}n}}\simeq 4^{\mathrm{o}}$
downtail to the Main spot Rabia . (2023).

From these latest observations, it therefore appears that the cyclotron maser
instability driven by a loss–cone electron distribution function is a common
way of amplifying radio emission at Jupiter. This is the case both for auroral
radio emission Louarn . (2017, 2018) and for moon–induced radio emission
<¿[and this present study]2020GeoRL..4790021L, 2022GeoRL..4996994H. We have
also shown here that the presence of Alfvénic perturbation as well as field
aligned current are necessary for the radio emissions to be amplified. The
radio sources are located only in the downward part of the FAC, i.e. when the
current is carried by upgoing electrons. This supports the results obtained
from very high resolution observations Zarka . (1996); Zarka (2004); Hess .
(2007a, 2007b); Louis . (2022), which show that the millisecond bursts
observed in the J–I emissions present only negative drifts, i.e. upward–moving
electrons. Finally, radio emission are found to be associated with TEB, MAW
and RAW spot at the footprint of the flux tube connected to the moons.

However, the Cyclotron Maser Instability does not trigger radio emission at a
detectable level for Waves every time Juno is in the flux tube of the moons,
even if UV emission is observed at the footprint of the flux tube in each
case. Radio sources are crossed in the two cases of Ganymede flux tube
crossings. In contrast, a radio source is crossed only once over ten Europa
flux tube crossings, while for Io, only four radio sources are crossed over 23
Io flux tube crossings. Therefore, it is clear that several criteria are
necessary to amplify a radio wave through the CMI.

First, we knew that for the CMI to occur, a low energetic plasma is needed
($f_{pe}/f_{ce}\ll 0.1$). But in this study, we also found that the CMI needs
to have a sufficiently dense, hot and energetic plasma to occur. If the ratio
between $f_{pe}$ and $f_{ce}$ is too low, the integration of the $\delta
f/\delta v_{\perp}$ gradient along the resonant circles gives an
insufficiently high growth rate to amplify the wave to an observable
intensity.

A second necessary condition seems to be the presence of an Alfvénic
acceleration process and Field Aligned Current. Could the loss–cone–driven CMI
be triggered by upward electrons accelerated by a Fermi acceleration process
in the FAC generated by the Alfvén Waves <as suggested by¿[]1997JGR…102…37C.
To answer this question, more crossings of Jupiter-Moon radio emissions will
be necessary, and future Juno observations could further illuminate these
important processes.

## Data Availability Statement

The Juno data used in this manuscript are found at the Planetary Data System
at https://doi.org/10.17189/1522461 for Waves data Kurth Piker (2022), at
https://doi.org/10.17189/1519715 for JADE–E data Allegrini . (2022) and at
https://doi.org/10.17189/1519711 for MAG data Connerney (2017).

###### Acknowledgements.

The authors thank the Juno mission team, especially the staff of the Waves,
JADE and MAG instruments. C. K. L.’s work at IRAP was supported by CNES. CKL’s
and CMJ’s work at DIAS was supported by Science Foundation Ireland Grant
18/FRL/6199. C. K. L. thanks E. Penou, for the help with the particle analysis
through the CLWeb software. V. H. acknowledges support from the French
government under the France 2030 investment plan, as part of the Initiative
d’Excellence d’Aix–Marseille Université – A*MIDEX AMX–22–CPJ–04. The research
at the University of Iowa is supported by NASA through Contract 699041X with
the Southwest Research Institute. The research at the Southwest Research
Institute is supported by NASA New Frontiers Program for Juno through contract
NNM06AA75C. The french authors acknowledge support from CNES and CNRS/INSU
national programs of planetology (PNP) and heliophysics (PNST).

## References

  * Al Saati . (2022) 2022JGRA..12730586AAl Saati, S., Clément, N., Louis, C., Blanc, M., Wang, Y., André, N.Mauk, B.  202210\.  Magnetosphere-Ionosphere-Thermosphere Coupling Study at Jupiter Based on Juno’s First 30 Orbits and Modeling Tools Magnetosphere-Ionosphere-Thermosphere Coupling Study at Jupiter Based on Juno’s First 30 Orbits and Modeling Tools.  Journal of Geophysical Research (Space Physics)12710e2022JA030586.  10.1029/2022JA030586
  * Allegrini . (2020) 2020GeoRL..4789732AAllegrini, F., Gladstone, GR., Hue, V., Clark, G., Szalay, JR., Kurth, WS.Wilson, RJ.  202009\.  First Report of Electron Measurements During a Europa Footprint Tail Crossing by Juno First Report of Electron Measurements During a Europa Footprint Tail Crossing by Juno.  Geophysical Research Letters4718e89732.  10.1029/2020GL089732
  * Allegrini . (2022) 2022_JADEE_pds_AllegriniAllegrini, F., Wilson, RJ., Ebert, RW. Loeffler, C.  2022\.  JJUNO J/SW JOVIAN AURORAL DISTRIBUTION CALIBRATED V1.0, JNO-J/SW-JAD-3-CALIBRATED-V1.0 [dataset]. JJUNO J/SW JOVIAN AURORAL DISTRIBUTION CALIBRATED V1.0, JNO-J/SW-JAD-3-CALIBRATED-V1.0 [dataset].  10.17189/1519715
  * Bagenal . (2017) 2017SSRv..213..219BBagenal, F., Adriani, A., Allegrini, F., Bolton, SJ., Bonfond, B., Bunce, EJ.Zarka, P.  201711\.  Magnetospheric Science Objectives of the Juno Mission Magnetospheric Science Objectives of the Juno Mission.  Space Science Reviews213219-287.  10.1007/s11214-014-0036-8
  * Bhattacharyya . (2018) 2018JGRA..123..364BBhattacharyya, D., Clarke, JT., Montgomery, J., Bonfond, B., Gérard, JC. Grodent, D.  201801\.  Evidence for Auroral Emissions From Callisto’s Footprint in HST UV Images Evidence for Auroral Emissions From Callisto’s Footprint in HST UV Images.  Journal of Geophysical Research (Space Physics)123364-373.  10.1002/2017JA024791
  * Bigg (1964) 1964Natur.203.1008BBigg, EK.  196409\.  Influence of the Satellite Io on Jupiter’s Decametric Emission Influence of the Satellite Io on Jupiter’s Decametric Emission.  Nature2031008-1010.  10.1038/2031008a0
  * Bonfond . (2017a) 2017Icar..292..208BBonfond, B., Grodent, D., Badman, SV., Saur, J., Gérard, JC. Radioti, A.  2017a08.  Similarity of the Jovian satellite footprints: Spots multiplicity and dynamics Similarity of the Jovian satellite footprints: Spots multiplicity and dynamics.  Icarus292208-217.  10.1016/j.icarus.2017.01.009
  * Bonfond . (2017b) 2017JGRA..122.7985BBonfond, B., Saur, J., Grodent, D., Badman, SV., Bisikalo, D., Shematovich, V.Radioti, A.  2017b08.  The tails of the satellite auroral footprints at Jupiter The tails of the satellite auroral footprints at Jupiter.  Journal of Geophysical Research (Space Physics)12287985-7996.  10.1002/2017JA024370
  * Clarke (1998) 1998…FGH767CClarke, JT.  1998\.  Hubble Space Telescope imaging of Jupiter’s UV aurora during the Galileo orbiter mission Hubble space telescope imaging of jupiter’s uv aurora during the galileo orbiter mission.  Journal of Geophysical Research: Planets103E920217-20236.  10.1029/98JE01130
  * Clarke . (2002) 2002Natur.415..997CClarke, JT., Ajello, J., Ballester, G., Ben Jaffel, L., Connerney, J., Gérard, JC.Waite, JH.  200202\.  Ultraviolet emissions from the magnetic footprints of Io, Ganymede and Europa on Jupiter Ultraviolet emissions from the magnetic footprints of Io, Ganymede and Europa on Jupiter.  Nature415997-1000.
  * Collet . (2023) 2023_Collet_PRE9Collet, B., Lamy, L., Louis, CK., Zarka, P., Prangé, R., Louarn, P.Kurth, WS.  2023\.  Characterization of Jovian hectometric sources with Juno: statistical position and generation by shell–type electrons Characterization of Jovian hectometric sources with Juno: statistical position and generation by shell–type electrons.  CK. Louis, Jackman, C. M., G. Fischer, AH. Sulaiman P. Zucca (), Planetary, Solar and Helispheric Radio Emissions IX. Planetary, solar and helispheric radio emissions ix.  Trinity College Dublin, Ireland.  10.25546/103095
  * Connerney (2017) 2017_FGM_pds_ConnerneyConnerney, JEP.  2017\.  Juno MAG CALIBRATED DATA J V1.0, JNO-J-3-FGM-CAL-V1.0 [dataset]. Juno MAG CALIBRATED DATA J V1.0, JNO-J-3-FGM-CAL-V1.0 [dataset].  10.17189/1519711
  * Connerney . (1981) 1981JGR….86.8370CConnerney, JEP., Acuna, MH. Ness, NF.  198109\.  Modeling the Jovian current sheet and inner magnetosphere Modeling the Jovian current sheet and inner magnetosphere.  Journal of Geophysics Research868370-8384.  10.1029/JA086iA10p08370
  * Connerney . (1993) 1993Sci…262.1035CConnerney, JEP., Baron, R., Satoh, T. Owen, T.  199311\.  Images of Excited H_3^+ at the Foot of the Io Flux Tube in Jupiter’s Atmosphere Images of Excited H_3^+ at the Foot of the Io Flux Tube in Jupiter’s Atmosphere.  Science2621035-1038.  10.1126/science.262.5136.1035
  * Connerney . (2017) 2017SSRv..213…39CConnerney, JEP., Benn, M., Bjarno, JB., Denver, T., Espley, J., Jorgensen, JL.Smith, EJ.  201711\.  The Juno Magnetic Field Investigation The Juno Magnetic Field Investigation.  Space Science Reviews21339-138.  10.1007/s11214-017-0334-z
  * Connerney . (2018) 2018GeoRL..45.2590CConnerney, JEP., Kotsiaros, S., Oliversen, RJ., Espley, JR., Joergensen, JL., Joergensen, PS.Levin, SM.  201803\.  A New Model of Jupiter’s Magnetic Field From Juno’s First Nine Orbits A New Model of Jupiter’s Magnetic Field From Juno’s First Nine Orbits.  Geophysical Research Letters452590-2596.  10.1002/2018GL077312
  * Crary (1997) 1997JGR…102…37CCrary, FJ.  199701\.  On the generation of an electron beam by Io On the generation of an electron beam by Io.  Journal of Geophysical Research102A137-50.  10.1029/96JA02409
  * Gershman . (2019) 2019GeoRL..46.7157GGershman, DJ., Connerney, JEP., Kotsiaros, S., DiBraccio, GA., Martos, YM., -Viñas, AF.Bolton, SJ.  201907\.  Alfvénic Fluctuations Associated With Jupiter’s Auroral Emissions Alfvénic Fluctuations Associated With Jupiter’s Auroral Emissions.  Geophysical Research Letters46137157-7165.  10.1029/2019GL082951
  * Gladstone . (2017) 2017SSRv..213..447GGladstone, GR., Persyn, SC., Eterno, JS., Walther, BC., Slater, DC., Davis, MW.Denis, F.  201711\.  The Ultraviolet Spectrograph on NASA’s Juno Mission The Ultraviolet Spectrograph on NASA’s Juno Mission.  Space Science Reviews213447-473.  10.1007/s11214-014-0040-z
  * Goldreich Lynden-Bell (1969) 1969ApJ…156…59GGoldreich, P. Lynden-Bell, D.  196904\.  Io, a jovian unipolar inductor Io, a jovian unipolar inductor.  Astrophysical Journal15659-78.  10.1086/149947
  * Hess . (2008) 2008GeoRL..3513107HHess, SLG., Cecconi, B. Zarka, P.  2008jul.  Modeling of Io-Jupiter decameter arcs, emission beaming and energy source Modeling of Io-Jupiter decameter arcs, emission beaming and energy source.  Geophysical Research Letters35L13107.  10.1029/2008GL033656
  * Hess . (2010) 2010JGRA..115.6205HHess, SLG., Delamere, P., Dols, V., Bonfond, B. Swift, D.  2010jun.  Power transmission and particle acceleration along the Io flux tube Power transmission and particle acceleration along the Io flux tube.  Journal of Geophysical Research (Space Physics)115A06205.  10.1029/2009JA014928
  * Hess . (2007b) 2007JGRA..11211212HHess, SLG., Mottez, F. Zarka, P.  2007b11.  Jovian S burst generation by Alfvén waves Jovian S burst generation by Alfvén waves.  Journal of Geophysical Research (Space Physics)112A11A11212.  10.1029/2006JA012191
  * Hess . (2007a) 2007P&SS…55…89HHess, SLG., Zarka, P. Mottez, F.  2007a01.  Io Jupiter interaction, millisecond bursts and field-aligned potentials Io Jupiter interaction, millisecond bursts and field-aligned potentials.  Planetary Space Science551-289-99.  10.1016/j.pss.2006.05.016
  * Higgins (2007) 2007JGRA..112.5213HHiggins, CA.  200705\.  Satellite control of Jovian 2-6 MHz radio emission using Voyager data Satellite control of Jovian 2-6 MHz radio emission using Voyager data.  Journal of Geophysical Research (Space Physics)112A05213.  10.1029/2006JA012100
  * Hue . (2023) 2023JGRA..12831363HHue, V., Gladstone, GR., Louis, CK., Greathouse, TK., Bonfond, B., Szalay, JR.Connerney, JEP.  202305\.  The Io, Europa, and Ganymede Auroral Footprints at Jupiter in the Ultraviolet: Positions and Equatorial Lead Angles The Io, Europa, and Ganymede Auroral Footprints at Jupiter in the Ultraviolet: Positions and Equatorial Lead Angles.  Journal of Geophysical Research (Space Physics)1285e2023JA031363.  10.1029/2023JA031363
  * Hue . (2022) 2022GeoRL..4996994HHue, V., Szalay, JR., Greathouse, TK., Bonfond, B., Kotsiaros, S., Louis, CK.Mauk, BH.  202204\.  A Comprehensive Set of Juno In Situ and Remote Sensing Observations of the Ganymede Auroral Footprint A Comprehensive Set of Juno In Situ and Remote Sensing Observations of the Ganymede Auroral Footprint.  Geophysical Research Letters497e96994.  10.1029/2021GL096994
  * Imai . (2019) 2019GeoRL..46..571IImai, M., Greathouse, TK., Kurth, WS., Gladstone, GR., Louis, CK., Zarka, P.Connerney, JEP.  2019Jan.  Probing Jovian Broadband Kilometric Radio Sources Tied to the Ultraviolet Main Auroral Oval With Juno Probing Jovian Broadband Kilometric Radio Sources Tied to the Ultraviolet Main Auroral Oval With Juno.  Geophysical Research Letters462571-579.  10.1029/2018GL081227
  * Imai . (2017) 2017GeoRL..44.6508IImai, M., Kurth, WS., Hospodarsky, GB., Bolton, SJ., Connerney, JEP. Levin, SM.  201707\.  Direction-finding measurements of Jovian low-frequency radio components by Juno near Perijove 1 Direction-finding measurements of Jovian low-frequency radio components by Juno near Perijove 1.  Geophysical Research Letters446508-6516.  10.1002/2017GL072850
  * Jácome . (2022) 2022A&A…665A..67JJácome, HRP., Marques, MS., Zarka, P., Echer, E., Lamy, L. Louis, CK.  202209\.  Search for Jovian decametric emission induced by Europa on the extensive Nançay Decameter Array catalog Search for Jovian decametric emission induced by Europa on the extensive Nançay Decameter Array catalog.  Astronomy & Astrophysics665A67.  10.1051/0004-6361/202244246
  * Kotsiaros . (2019) 2019NatAs…3..904KKotsiaros, S., Connerney, JEP., Clark, G., Allegrini, F., Gladstone, GR., Kurth, WS.Levin, SM.  201907\.  Birkeland currents in Jupiter’s magnetosphere observed by the polar-orbiting Juno spacecraft Birkeland currents in Jupiter’s magnetosphere observed by the polar-orbiting Juno spacecraft.  Nature Astronomy3904-909.  10.1038/s41550-019-0819-7
  * Kurth . (2011) 2011pre7.conf…75KKurth, WS., Gurnett, DA., Menietti, JD., Mutel, RL., Kivelson, MG., Bunce, EJ.Morooka, M.  201101\.  A Close Encounter with a Saturn Kilometric Radiation Source Region A Close Encounter with a Saturn Kilometric Radiation Source Region.  HO. Rucker, WS. Kurth, P. Louarn G. Fischer (), Planetary, Solar and Heliospheric Radio Emissions (PRE VII) Planetary, solar and heliospheric radio emissions (pre vii) ( 75-85).
  * Kurth . (2017) 2017SSRv..213..347KKurth, WS., Hospodarsky, GB., Kirchner, DL., Mokrzycki, BT., Averkamp, TF., Robison, WT.Zarka, P.  201711\.  The Juno Waves Investigation The Juno Waves Investigation.  Space Science Reviews213347-392.  10.1007/s11214-017-0396-y
  * Kurth Piker (2022) 2022_waves_survey_KurthKurth, WS. Piker, CW.  2022\.  JUNO E/J/S/SS WAVES CALIBRATED BURST FULL RESOLUTION V2.0, JNO-E/J/SS-WAV-3-CDR-BSTFULL-V2.0 [dataset. JUNO E/J/S/SS WAVES CALIBRATED BURST FULL RESOLUTION V2.0, JNO-E/J/SS-WAV-3-CDR-BSTFULL-V2.0 [dataset.  10.17189/1522461
  * Lamy . (2022) 2022JGRA..12730160LLamy, L., Colomban, L., Zarka, P., Prangé, R., Marques, MS., Louis, CK.Yerin, S.  202204\.  Determining the Beaming of Io Decametric Emissions: A Remote Diagnostic to Probe the Io-Jupiter Interaction Determining the Beaming of Io Decametric Emissions: A Remote Diagnostic to Probe the Io-Jupiter Interaction.  Journal of Geophysical Research (Space Physics)1274e30160.  10.1029/2021JA030160
  * Lamy . (2023) 2023PREIX_LamyLamy, L., Duchêne, A., Mauduit, E., Zarka, P., Yerin, S., Louis, C.Theureau, G.  2023\.  Probing Jupiter-satellite interactions from the beaming of their decametric emissions: the case of Europa and Ganymede Probing Jupiter-satellite interactions from the beaming of their decametric emissions: the case of Europa and Ganymede.  CK. Louis, Jackman, C. M., G. Fischer, AH. Sulaiman P. Zucca (), Planetary, Solar and Heliospheric Radio Emissions IX. Planetary, solar and heliospheric radio emissions IX.  Trinity Dublin College, Ireland.  10.25546/103097
  * Lamy . (2010) 2010GeoRL..3712104LLamy, L., Schippers, P., Zarka, P., Cecconi, B., Arridge, CS., Dougherty, MK.Coates, AJ.  201006\.  Properties of Saturn kilometric radiation measured within its source region Properties of Saturn kilometric radiation measured within its source region.  Geophysical Research Letters3712L12104.  10.1029/2010GL043415
  * Le Queau . (19841) 1984PhFl…27..247LLe Queau, D., Pellat, R. Roux, A.  1984101\.  Direct generation of the auroral kilometric radiation by the maser synchrotron instability: An analytical approach Direct generation of the auroral kilometric radiation by the maser synchrotron instability: An analytical approach.  Physics of Fluids271247-265.  10.1063/1.864520
  * Le Queau . (19842) 1984JGR….89.2831LLe Queau, D., Pellat, R. Roux, A.  1984205\.  Direct generation of the auroral kilometric radiation by the maser synchrotron instability: Physical mechanism and parametric study Direct generation of the auroral kilometric radiation by the maser synchrotron instability: Physical mechanism and parametric study.  Journal of Geophysical Research89A52831-2841.  10.1029/JA089iA05p02831
  * Louarn . (2017) 2017GeoRL..44.4439LLouarn, P., Allegrini, F., McComas, DJ., Valek, PW., Kurth, WS., André, N.Zink, JL.  201705\.  Generation of the Jovian hectometric radiation: First lessons from Juno Generation of the Jovian hectometric radiation: First lessons from Juno.  Geophysical Research Letters444439-4446.  10.1002/2017GL072923
  * Louarn . (2018) 2018GeoRL..45.9408LLouarn, P., Allegrini, F., McComas, DJ., Valek, PW., Kurth, WS., André, N.Wilson, RJ.  201809\.  Observation of Electron Conics by Juno: Implications for Radio Generation and Acceleration Processes Observation of Electron Conics by Juno: Implications for Radio Generation and Acceleration Processes.  Geophysical Research Letters45189408-9416.  10.1029/2018GL078973
  * Louis . (2019b) 2019A&A…627A..30LLouis, CK., Hess, SLG., Cecconi, B., Zarka, P., Lamy, L., Aicardi, S. Loh, A.  2019bJul.  ExPRES: an Exoplanetary and Planetary Radio Emissions Simulator ExPRES: an Exoplanetary and Planetary Radio Emissions Simulator.  Astronomy & Astrophysics627A30.  10.1051/0004-6361/201935161
  * Louis . (2022) 2022RASTI…1…48LLouis, CK., Jackman, CM., Grießmeier, JM., Wucknitz, O., McKenna, DJ., Murphy, PC.Vocks, C.  202204\.  Method to observe Jupiter’s radio emissions at high resolution using multiple LOFAR stations: a first case study of the Io-decametric emission using the Irish IE613, French FR606, and German DE604 stations Method to observe Jupiter’s radio emissions at high resolution using multiple LOFAR stations: a first case study of the Io-decametric emission using the Irish IE613, French FR606, and German DE604 stations.  RAS Techniques and Instruments1148-57.  10.1093/rasti/rzac005
  * Louis . (2017b) 2017JGRA..122.9228LLouis, CK., Lamy, L., Zarka, P., Cecconi, B. Hess, SLG.  2017b09.  Detection of Jupiter decametric emissions controlled by Europa and Ganymede with Voyager/PRA and Cassini/RPWS Detection of Jupiter decametric emissions controlled by Europa and Ganymede with Voyager/PRA and Cassini/RPWS.  Journal of Geophysical Research (Space Physics)1229228-9247.  10.1002/2016JA023779
  * Louis . (2017a) 2017GeoRL..44.9225LLouis, CK., Lamy, L., Zarka, P., Cecconi, B., Imai, M., Kurth, WS.Levin, SM.  2017a09.  Io-Jupiter decametric arcs observed by Juno/Waves compared to ExPRES simulations Io-Jupiter decametric arcs observed by Juno/Waves compared to ExPRES simulations.  Geophysical Research Letters449225-9232.  10.1002/2017GL073036
  * Louis . (2020) 2020GeoRL..4790021LLouis, CK., Louarn, P., Allegrini, F., Kurth, WS. Szalay, JR.  202010\.  Ganymede-Induced Decametric Radio Emission: In Situ Observations and Measurements by Juno Ganymede-Induced Decametric Radio Emission: In Situ Observations and Measurements by Juno.  Geophysical Research Letters4720e90021.  10.1029/2020GL090021
  * Louis . (2019a) 2019GeoRL..4611606LLouis, CK., Prangé, R., Lamy, L., Zarka, P., Imai, M., Kurth, WS. Connerney, JEP.  2019a11.  Jovian Auroral Radio Sources Detected In Situ by Juno/Waves: Comparisons With Model Auroral Ovals and Simultaneous HST FUV Images Jovian Auroral Radio Sources Detected In Situ by Juno/Waves: Comparisons With Model Auroral Ovals and Simultaneous HST FUV Images.  Geophysical Research Letters462111,606-11,614.  10.1029/2019GL084799
  * McComas . (2017) 2017SSRv..213..547MMcComas, DJ., Alexander, N., Allegrini, F., Bagenal, F., Beebe, C., Clark, G.White, D.  201711\.  The Jovian Auroral Distributions Experiment (JADE) on the Juno Mission to Jupiter The Jovian Auroral Distributions Experiment (JADE) on the Juno Mission to Jupiter.  Space Science Reviews213547-643.  10.1007/s11214-013-9990-9
  * Menietti . (2001) 2001GeoRL..28.3047MMenietti, JD., Gurnett, DA. Christopher, I.  2001\.  Control of Jovian radio emission by Callisto Control of Jovian radio emission by Callisto.  Geophysical Research Letters283047-3050.  10.1029/2001GL012965
  * Mura . (2017) 2017GeoRL..44.5308MMura, A., Adriani, A., Altieri, F., Connerney, JEP., Bolton, SJ., Moriconi, ML.Olivieri, A.  201706\.  Infrared observations of Jovian aurora from Juno’s first orbits: Main oval and satellite footprints Infrared observations of Jovian aurora from Juno’s first orbits: Main oval and satellite footprints.  Geophysical Research Letters44115308-5316.  10.1002/2017GL072954
  * Mura . (2018) 2018Sci…361..774MMura, A., Adriani, A., Connerney, JEP., Bolton, S., Altieri, F., Bagenal, F.Turrini, D.  201808\.  Juno observations of spot structures and a split tail in Io-induced aurorae on Jupiter Juno observations of spot structures and a split tail in Io-induced aurorae on Jupiter.  Science3616404774-777.  10.1126/science.aat1450
  * Mutel . (2010) 2010GeoRL..3719105MMutel, RL., Menietti, JD., Gurnett, DA., Kurth, W., Schippers, P., Lynch, C.Cecconi, B.  201010\.  CMI growth rates for Saturnian kilometric radiation CMI growth rates for Saturnian kilometric radiation.  Geophysical Research Letters3719L19105.  10.1029/2010GL044940
  * Neubauer (1980) 1980JGR….85.1171NNeubauer, FM.  198003\.  Nonlinear standing Alfven wave current system at Io - Theory Nonlinear standing Alfven wave current system at Io - Theory.  Journal of Geophysics Research851171-1178.  10.1029/JA085iA03p01171
  * Prangé . (1996) 1996Natur.379..323PPrangé, R., Rego, D., Southwood, D., Zarka, P., Miller, S. Ip, W.  199601\.  Rapid energy dissipation and variability of the lo-Jupiter electrodynamic circuit Rapid energy dissipation and variability of the lo-Jupiter electrodynamic circuit.  Nature379323-325.  10.1038/379323a0
  * Pritchett (1986) 1986JGR….9113569PPritchett, PL.  198612\.  Cyclotron maser radiation from a source structure localized perpendicular to the ambient magnetic field Cyclotron maser radiation from a source structure localized perpendicular to the ambient magnetic field.  Journal of Geophysical Research91A1213569-13582.  10.1029/JA091iA12p13569
  * Rabia . (2023) 2023RabiaGRLRabia, J., Hue, V., Szalay, JR., André, N., Nénon, Q., Blanc, M.Sulaiman, AH.  2023\.  Evidence for Non-Monotonic and Broadband Electron Distributions in the Europa Footprint Tail Revealed by Juno In Situ Measurements Evidence for non-monotonic and broadband electron distributions in the europa footprint tail revealed by juno in situ measurements.  Geophysical Research Letters5012e2023GL103131.  https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2023GL103131 e2023GL103131 2023GL103131  https://doi.org/10.1029/2023GL103131
  * Saur (2004) 2004JGRA..109.1210SSaur, J.  200401\.  A model of Io’s local electric field for a combined Alfvénic and unipolar inductor far-field coupling A model of Io’s local electric field for a combined Alfvénic and unipolar inductor far-field coupling.  Journal of Geophysical Research (Space Physics)109A01210.  10.1029/2002JA009354
  * Szalay . (2020a) 2020GeoRL..4786527SSzalay, JR., Allegrini, F., Bagenal, F., Bolton, SJ., Bonfond, B., Clark, G.Wilson, RJ.  2020a02.  Alfvénic Acceleration Sustains Ganymede’s Footprint Tail Aurora Alfvénic Acceleration Sustains Ganymede’s Footprint Tail Aurora.  Geophysical Research Letters473e86527.  10.1029/2019GL086527
  * Szalay . (2020b) 2020GeoRL..4789267SSzalay, JR., Allegrini, F., Bagenal, F., Bolton, SJ., Bonfond, B., Clark, G.Wilson, RJ.  2020b09.  A New Framework to Explain Changes in Io’s Footprint Tail Electron Fluxes A New Framework to Explain Changes in Io’s Footprint Tail Electron Fluxes.  Geophysical Research Letters4718e89267.  10.1029/2020GL089267
  * Szalay . (2018) 2018JGRE..123.3061SSzalay, JR., Bonfond, B., Allegrini, F., Bagenal, F., Bolton, S., Clark, G.Wilson, RJ.  201811\.  In Situ Observations Connected to the Io Footprint Tail Aurora In Situ Observations Connected to the Io Footprint Tail Aurora.  Journal of Geophysical Research (Planets)123113061-3077.  10.1029/2018JE005752
  * Szalay . (2022) 2022GeoRL..4998111SSzalay, JR., Smith, HT., Zirnstein, EJ., McComas, DJ., Begley, LJ., Bagenal, F.Bolton, SJ.  202205\.  Water-Group Pickup Ions From Europa-Genic Neutrals Orbiting Jupiter Water-Group Pickup Ions From Europa-Genic Neutrals Orbiting Jupiter.  Geophysical Research Letters499e98111.  10.1029/2022GL098111
  * Treumann (2006) 2006A&ARv..13..229TTreumann, RA.  200608\.  The electron-cyclotron maser for astrophysical application The electron-cyclotron maser for astrophysical application.  Astronomy & Astrophysicsr13229-315.  10.1007/s00159-006-0001-y
  * Wang . (2021) 2021JGRA..12629469WWang, Y., Blanc, M., Louis, C., Wang, C., André, N., Adriani, A.Tao, C.  202109\.  A Preliminary Study of Magnetosphere-Ionosphere-Thermosphere Coupling at Jupiter: Juno Multi-Instrument Measurements and Modeling Tools A Preliminary Study of Magnetosphere-Ionosphere-Thermosphere Coupling at Jupiter: Juno Multi-Instrument Measurements and Modeling Tools.  Journal of Geophysical Research (Space Physics)1269e29469.  10.1029/2021JA029469
  * Wu (1985) 1985SSRv…41..215WWu, CS.  198508\.  Kinetic cyclotron and synchrotron maser instabilities - Radio emission processes by direct amplification of radiation Kinetic cyclotron and synchrotron maser instabilities - Radio emission processes by direct amplification of radiation.  Space Science Reviews41215-298.  10.1007/BF00190653
  * Wu Lee (1979) 1979ApJ…230..621WWu, CS. Lee, LC.  197906\.  A theory of the terrestrial kilometric radiation. A theory of the terrestrial kilometric radiation.  Astrophysical Journal230621-626.  10.1086/157120
  * Zarka (2004) 2004P&SS…52.1455ZZarka, P.  200412\.  Fast radio imaging of Jupiter’s magnetosphere at low-frequencies with LOFAR Fast radio imaging of Jupiter’s magnetosphere at low-frequencies with LOFAR.  Planetary Space Science52151455-1467.  10.1016/j.pss.2004.09.017
  * Zarka . (1996) 1996GeoRL..23..125ZZarka, P., Farges, T., Ryabov, BP., Abada-Simon, M. Denis, L.  199601\.  A scenario for Jovian S-bursts A scenario for Jovian S-bursts.  Geophysical Research Letters232125-128.  10.1029/95GL03780
  * Zarka . (2017) 2017pre8.conf…45ZZarka, P., Marques, MS., Louis, C., Ryabov, VB., Lamy, L., Echer, E. Cecconi, B.  201701\.  Radio emission from satellite-Jupiter interactions (especially Ganymede) Radio emission from satellite-Jupiter interactions (especially Ganymede).  G. Fischer, G. Mann, M. Panchenko P. Zarka (), Planetary Radio Emissions VIII Planetary radio emissions viii ( 45-58).  10.1553/PRE8s45
  * Zarka . (2018) 2018A&A…618A..84ZZarka, P., Marques, MS., Louis, C., Ryabov, VB., Lamy, L., Echer, E. Cecconi, B.  201810\.  Jupiter radio emission induced by Ganymede and consequences for the radio detection of exoplanets Jupiter radio emission induced by Ganymede and consequences for the radio detection of exoplanets.  Astronomy & Astrophysics618A84.  10.1051/0004-6361/201833586