Martian dust can be lifted to about 100 kilometres by known processes such as dust storms (e.g. Heavens et al, J. Atmos. Sci. 76, 2019). Dust has been observed at higher altitudes, but this is attributed to capture of interplanetary dust (Andersson et al, Science 250, 2015).During its flight from Earth to Jupiter, a star camera on the Juno spacecraft observed dust in the size range of 1-100 um, contributing to the Zodiacal light and sharing orbital elements with Mars (Jørgensen et al, JGR: Planets 126, 2020). The origin of this dust was speculated to be Mars itself but a mechanism that allows the dust to reach escape velocity (~5 km/s) has not yet been identified. While dust can theoretically be lofted to hundreds of kilometres by electric forces on, for instance, the Moon (Wang et al, Planet. Space Sci. 184, 2020), the Martian atmosphere (thin as it is) makes this more difficult.In this work we investigate the possibility of dust escaping Mars by electric forces. In order to reach the escape velocity a dust particle must overcome the forces of gravity and atmospheric drag. Beyond altitudes reached by meteorological phenomena, only electric forces can accelerate the particles. Recently observations by the Perseverance rover (Chide et al, Nature 647, 2025) showed discharges during dust events, indicating that the Martian atmosphere can have breakdown fields (about 15 kV/m at ground level).In our model a dust particle of a prescribed size, charge, and updraft velocity is released at a given altitude into an atmosphere with an altitude dependent electric field. The resulting electric, drag, and gravity forces are calculated to find the particle’s velocity and altitude as a function of time. We test limit cases of electric charge and fields for relevant particle sizes to see what velocity is reached and how far a particle can be lifted.

Various characteristic frequencies observed in the plasma wave spectrum inward of Io have revealed a durable electron density profile that includes a localized relative maximum near M = 4.8 with a local minimum between this and the much greater densities closer to Io. Scale heights relative to the centrifugal equator are of order one Jovian radius, thought to be too large for a cold heavy ion population leading to the conclusion that protons are likely responsible for the large scale height. In this paper we show evidence of the low-frequency cutoff of the z-mode at the L=0 frequency, a polarization change at the local electron plasma frequency and low-frequency cutoff of ordinary mode waves. The determination of the electron plasma frequency and electron cyclotron frequency from the measured magnetic field strength also allow the calculation of the upper hybrid resonance frequency and R=0 cutoff of the extraordinary mode. Often, all of these spectral features can be found in the Juno plasma wave spectra obtained in the inner Io torus.

Albedo changes of Neptune related to the 11-year solar cycle have been reported since the 1970s (Lockwood and Thompson, Nature 280, 1979). For nearly two decades a clear anti-correlation between solar activity and Neptune’s brightness was observed but the relationship appeared to break down between the late 1980s (Lockwood and Thompson, Nature 349, 1991) and mid 1990s (Lockwood and Jerzykieicz, Icarus 180(2), 2006) where signs of a direct correlation instead appeared. Recent results indicate a direct correlation sustained over two solar cycles (Chavez et al, Icarus 404, 2023) prompting renewed interest in attempting an explanation. Several parameters vary with the solar cycle, one being UV light which has a much higher variation than that of visible light. This could affect the photochemistry of Neptune’s atmosphere which is rich in methane that photolyzes at wavelengths below 200 nm and can produce haze (Romani and Atreya, Icarus 74(3), 1988). Another parameter that varies is the flux of galactic cosmic rays (GCRs) which is modulated by the solar wind. GCRs can ionize molecules leading to ion-induced nucleation (Moses et al, GRL 16(12), 1989) but only for the energies of particles which are allowed entry to the planetary atmosphere by the magnetic field. Solar activity modulates GCRs of energies up to about 20 GeV so a solar variation due to GCRs is only possible if particles of those energies can enter the atmosphere. The parameter used to describe GCR entry is the cutoff rigidity (in GV). In this work we have used the magnetic field model of Neptune (Connerney et al, ASR 12(8), 1992) and a particle trajectory program (the Geomagnetic Cutoff Rigidity Computer Program by Smart and Shea, 2001, Tech. Rep. No. 20010071975) to calculate a cutoff rigidity map for Neptune for vertical GCR entry. Since the magnetic field is very tilted compared to the rotational axis (by about 45 degrees) the cutoff rigidity map has interesting features as the GCRs are guided by the magnetic field lines. Thus, lower energies and therefore a higher GCR flux more susceptible to solar cycle changes are allowed to enter the atmosphere at mid latitudes, as opposed to most planets where this happens as the poles since their magnetic field is more closely aligned with the rotational axis. Furthermore, we have used fitted GCR energy spectra in combination with the cutoff rigidity map to produce a map of solar cycle variations in GCR flux at a height of 49 km, which is at the pressure level where cosmic ray showers are initiated at Earth and also close to where Neptunian clouds are found. Where the cutoff rigidity is lowest the solar cycle variations of GCR are several tens of percents which could affect cloud formation significantly.

Juno's highly eccentric polar orbit takes it to perijove distances of 1.06 on each orbit. For the first perijove, this occurred just north of the jovigraphic equator, but has precessed north by about a degree per orbit over the mission. Minimum altitudes vary from 3,200–8,000 km through the mission. The Waves instrument observes a number of plasma wave modes in and near the non‐auroral ionosphere that provide information on the local electron number density, including electron plasma oscillations that occur at the electron plasma frequency and whistler‐mode hiss which has an upper frequency limit of in Jupiter's strongly magnetized inner magnetosphere. The electron plasma frequency provides the electron number density. We present electron densities in the topside ionosphere, similar to Earth's F2 layer, from the 59 perijoves analyzed to date. Peak densities range from 100 to 80,000 at latitudes up to . The density profiles can be highly variable from one perijove to the next. And, there can be deviations from simple smooth variations with altitude within individual ionospheric passes. Spatial variations may be responsible for some of the variability, perhaps related to Jupiter's complex magnetic field. We show the variation in ionospheric density profiles and the distribution of peak densities as a function of latitude and longitude as well as other geometric parameters. In addition to the complex magnetic field, possible factors affecting ionospheric density variations investigated here are ionospheric dynamos analogous to those at Earth and precipitation of energetic particles.

Recently, it has been shown that the secular variation of Jupiter's magnetic field, which has been observed by the Juno spacecraft, is in large part due to eastward advection of the Great Blue Spot (a localized, equatorial region of intense magnetic field) by fluid flow in the deep interior. More recent observations by Juno suggest that the drift rate of the spot is varying rapidly in time. These time variations can be fit with a sinusoidal variation of the flow speed with a period of approximately four years. Here, we discuss both the mechanism of this time variability and the constraints that its observability place on the structure and dynamics of the deep interior.

Energetic Neutral Atom (ENA) cameras on orbiting spacecraft at Earth and Saturn have helped greatly to diagnose these complex magnetospheres. Within this decade, the European Space Agency’s Jupiter Icy Moons Explorer (JUICE) mission will arrive at Jupiter and make ENA imaging a major thrust in helping to understand its complex magnetosphere. The present polar-orbiting Juno mission carries no ENA camera, but the energetic particle JEDI instrument is serendipitously sensitive to ENA’s with energies > 50 keV, provided there are no charged particles in the environment to mask their presence. Juno offers great service to the interpretation of both past and future ENA imaging with its orbit allowing unique viewing perspectives. Here we report on several components of ENA emissions that can probe the dynamical state of the regions involved, including the space environment of the orbit of Io, that of Europa, and Jupiter itself. A special focus here will be new observations of ENA emissions from Jupiter’s polar regions, the proper interpretation of which may end up being unique to the Juno mission, even after the JUICE mission.

A map of vertical cutoff rigidities has been calculated for galactic cosmic ray (GCR) entry into the atmosphere of Jupiter at the 1 bar pressure radius (1 RJ = 71,492 km) using the JRM33 comprehensive model of Jupiter's magnetic field (based on 32 close flybys of Jupiter by the Juno satellite) along with a particle trajectory code (Geomagnetic Cutoff Rigidity Computer Program). The map was combined with measurements of the GCR proton flux at Earth, from the BESS-Polar ii campaign, to calculate a corresponding proton flux map at Jupiter. Additional cutoff rigidity maps were calculated for 1,000 km above the 1 bar level, and for 1.41 RJ. Furthermore, detections of heavy particles from Juno's Stellar Reference Unit were analyzed for their cutoff rigidities in multiple directions. Cutoff rigidities of 3.5-7.5 GV were found for five of the detections furthest out making them possible GCR candidates. The majority of points, located below 1.6 RJ are not likely to be GCR. Assuming instead that they are trapped particles we have calculated upper and lower limits on their equatorial pitch angles, resulting in a range from 10.1 degrees to 27.1 degrees, which can help constraining Jupiter's energetic radiation. Using data of Jupiter's magnetic field, collected by the Juno satellite, we have calculated how galactic cosmic rays (energetic particles originating from supernovae) can enter into the atmosphere of Jupiter at different altitudes. This can aid our understanding of atmospheric phenomena on Jupiter and help in planning future missions to the planet. One of Juno's instruments, the Stellar Reference Unit, has detected some peculiar signatures. Some of them probably are galactic cosmic rays that have hit the instrument. Most of them are probably not, but instead they could be particles trapped by the strong magnetic field of Jupiter. If so, they can help us understand the radiation belts of the planet. Using knowledge of the location of the detections as well as the magnetic field we calculate the so-called pitch angle of the detected particles. This angle is defined by the ratio between the motion of the particle perpendicular to the magnet field line and the motion parallel to the field line. The pitch angle is fundamental in constraining energetic radiation emanating from Jupiter's atmosphere. A galactic cosmic ray cutoff rigidity map for Jupiter was made using the JRM33 model and the Geomagnetic Cutoff Rigidity Computer Program The flux of galactic cosmic ray protons into Jupiter's atmosphere was calculated based on BESS-Polar ii data Detections of heavy ions by Juno's SRU were investigated and used to estimate their equatorial pitch angles

The dynamics of the Jovian magnetosphere is controlled by the complex interplay of the planet’s fast rotation, its solar-wind interaction and its main plasma source at the Io torus. Juno observations have amply demonstrated that the Magnetosphere-Ionosphere-Thermosphere (MIT) coupling processes and regimes which control this interplay are significantly different from their Earth and Saturn counterparts. At the ionospheric level, these MIT coupling processes can be characterized by a set of key parameters which include ionospheric electrodynamic parameters (conductances, currents and electric fields), exchanges of particles along field lines and auroral emissions. Knowledge of these key parameters in turn makes it possible to estimate the net deposition/extraction of momentum and energy into/out of the Jovian upper atmosphere. We will present a method combining Juno multi-instrument data (MAG, JADE, JEDI, UVS, JIRAM and WAVES), adequate modelling tools (the TRANSPLANET ionospheric dynamics model and a simplified set of ionospheric current closure equations) and the AMDA data handling tools to provide preliminary estimates of these key parameters and their variation along the ionospheric footprint of Juno’s magnetic field line and across the auroral ovals for three of the first perijoves of the mission. We will discuss how this synergistic use of data and models can also contribute to provide a better determination of poorly known parameters such as the vertical structure of the auroral and polar Jovian neutral atmosphere.

Magnetic reconnection and current disruption are two key processes in driving energy conversion and dissipation in planetary magnetospheres. At the Earth, the two processes usually occur at different locations: the current disruption process occurs more frequently in the near-Earth magnetotail ∼10 R _E , while the magnetotail reconnection process is expected to take place in the more distant region where the current sheet is thinner. Occasionally, under very intense solar wind perturbations, reconnection could be located closer to the Earth where current disruption processes usually operate. But it is unclear what the situation is at giant planets, in which the plasma environment is very different from the Earth. In this study, we investigate a middle-Jupiter reconnection event at ∼43 R _J . During the event, the inferred integrated cross-field currents were substantially reduced, which we argue is a signature of current disruption. In this case, we suggest that magnetic reconnection could be colocated with a current disruption process in the Jovian magnetosphere, which is roughly analogous to the situation in the extremely perturbed Earth’s magnetosphere.

Magnetic flux ropes – helical magnetic structures which are produced due to simultaneous reconnection at multiple X-lines, have been observed at the magnetospheres of most magnetized planets. The size of these flux ropes, also called “plasmoids” if they contain significant plasma pressure, can vary from being a significant fraction of the system size (e.g. tens of Earth radii at the terrestrial magnetotail) to small flux ropes with diameters less than the local ion inertial length. The smallest flux ropes are expected because reconnection in the Earth’s cross-tail current sheet only occurs when it thins to or below the ion-inertial scale and tearing instabilities produce periodic X-lines with spacing of ~2 times the thickness of the current sheet. While much is still to be understood, it is hypothesized on the basis of Particle-in-Cell simulations that the smaller flux ropes soon come together and “coalesce”, via reconnection, into larger flux ropes. The coalescence process continues until the observed distribution of plasmoid diameters is produced. For the giant magnetospheres like Jupiter, which encompass multiple moons that lose mass to the rapidly rotating inner plasma disk, the momentum in the outer layers of the disk is believed to continuously shed mass by the release of plasmoids down the tail plasma sheet. This periodic ejection of plasmoids to balance the mass being added to the magnetosphere by Jupiter’s moons is termed the Vasyliunas-cycle. Rather than being formed by multiple x-line reconnection in a highly thinned current sheet, these Vasyliunas-cycle plasmoids are thought to form when a single X-line disconnects a highly stretched closed flux tube and allows its momentum to carry it down the tail. Due to the limited single-spacecraft measurements obtained by Galileo in the dusk-side magnetosphere, relatively little is known about these Vasyliunas-type plasmoids. Signatures of most Jovian plasmoids and flux ropes lasted ~6.8 minutes on average (Vogt et al., 2014), corresponding to diameters larger than 1 Jovian radii (RJ); much larger than the ion inertial length expected in the outer magnetosphere. Potential flux ropes on the ion-inertial scale, which would typically last for less than a minute could not have been identified using the Galileo magnetometer owing to the low cadence of several seconds per vector measurement. As part of its 53-day orbits, Juno spent a considerable amount of time in the dawn-side magnetotail. Using the high-resolution data from the Juno magnetometer, we identified two potential ion-scale flux ropes in the Jovian magnetotail by searching for bipolar variations in the magnetic field component normal to the current sheet. The two events were 22 s and 62 s in duration and were located at radial distances of roughly 74 RJ and 92 RJ between 03 and 04 local time. Assuming that the travel speed of the flux rope is limited by the Alfven speed in the surrounding magnetotail lobes, which is calculated using the plasma density inferred by the cutoff for the continuum radiation detected by the Waves instrument (0.003 to 0.012 cm-3), we estimated the diameters of these flux ropes to be 0.14 and 0.19 RJ respectively. The flux ropes’ diameters were comparable to the ion inertial length during these intervals, which was roughly between 0.11 to 0.23 RJ, (assuming a mass of 16.6 amu for the average ion). The selected events were analyzed using the minimum variance analysis and both events were seen to possess a strong core field with relatively high eigenvalue ratios, indicating that the MVA coordinate system was well-defined. Using a force-free model which is fitted to the observations, it was found that the flux ropes are quasi-force-free. These are the first reported observations of ion-scale flux ropes in the Jovian magnetotail. Although the large-scale dynamics of the magnetosphere may be dominated by the Vasyliunas cycle, the observations show that small-scale flux ropes, which are likely generated due to the tearing instability in a thin current sheet, also exist in the Jovian magnetotail, similar to the magnetotails of Earth and Mercury.

Since its orbital insertion around Jupiter on July 4, 2016, the Juno spacecraft has been navigating in a highly elliptical orbit, offering unprecedented insights into the gas giant's magnetosphere. A pivotal aspect of this mission is the analysis of the interaction between Jupiter's magnetic field and the surrounding plasma environment, particularly concerning the Io flux tube. The µASC, serving as an attitude reference for Juno's Magnetic Field investigation, has played a crucial role in continuously monitoring electron fluxes. These observations reveal a consistent depletion of electron fluxes in proximity to the Io flux tube. To date, Juno has completed 57 close approaches to Jupiter, known as perijoves, during which it has traversed the Io flux tube over 200 times. These encounters have provided a wealth of in-situ electron flux data, enabling a comprehensive profiling of the Io torus electron population.

On February 7th 2018, during Juno’s 11th perijove observation sequence, Juno’s ultraviolet spectrograph (Juno-UVS) unveiled the development of a dawn storm in Jupiter's aurorae. These auroral events consist of spectacular brightenings of the midnight to dawn sector of the main emissions at Jupiter. At the end of the sequence, Juno crossed the magnetic field lines connected to this dawn storm, unraveling some of the processes giving rise to these spectacular events. All in situ instruments detected a sharp transition as the spacecraft entered the dawn storm at an altitude of approximately 5RJ in the southern hemisphere. The particle fluxes detected by the JADE and JEDI instruments, including electrons and ions, increased dramatically. A strong flux of penetrating radiation was also detected by the UVS instrument. The Alfvén waves spectrograms derived from the MAG instrument also show a clear transition between a quiet and an extremely active regime as the spacecraft entered the dawn storm. Furthermore, the orientation of the magnetic field showed a very strong perturbation, associated with intense currents. And, finally, intense bKOM emissions were also observed during this time interval. Combined with the remote sensing observations of the aurora, these datasets strongly suggest that Juno witnessed a strong magnetospheric reconfiguration that started in the magneto-tail and then evolved toward dawn as the planet rotated.

At Mars, recent studies based on a combination of MAVEN data and modeling have determined the Martian magnetotail exhibits a ~45° twist, either clockwise or counterclockwise from the ecliptic plane, away from the nominal interplanetary magnetic field (IMF) draping morphology. An initial study by DiBraccio et al. [2018] employed MAVEN magnetic field measurements, coupled with MHD simulations, to indicate that the twist is likely a result of the sun-planetary interaction. Now with several more years of MAVEN data available, we augment this work using a statistical analysis of MAVEN magnetic field data from November 2014 through November 2019. We utilized ~6000 orbits, requiring that MAVEN observed both the magnetotail and the upstream IMF over a given orbit. For periods when the upstream IMF measurements were not available due to MAVEN’s orbit precession, we utilize an IMF proxy to determine characteristics of the upstream orientation. The location of the magnetotail lobes, identified in the data as the regions of magnetic field behind the planet directed towards and away from Mars, are analyzed as a function of the upstream IMF dawn-dusk component. In the previous DiBraccio et al. [2018] study, this dawn-dusk component was found to be the separating factor in the direction of magnetotail twisting. To quantify the degree of tail twisting for a given scenario, we determine the vector between the center of the towards/away tail lobes and calculate the angle between this vector and the expected direction for nominal IMF draping. This calculated tail twist angle is then assessed as a function of a variety of factors including strong crustal field location, Mars season, and downtail distance. In all cases, we determine that the degree of tail twisting is larger when the IMF is oriented in the duskward direction, suggesting enhanced coupling between the IMF and planetary crustal fields. Furthermore, we demonstrate that the degree of tail twisting exhibits different trends for crustal field orientation under dawnward versus duskward IMF configurations. Seasonal variations indicate that tail twisting may vary over the course of the Martian year, but additional data are needed during the northern fall and winter periods for confirmation. Finally, when assessing the tail twist with downtail distance we find that the degree of twisting increases with distance from the planet. This result is similar to Earth where observations of the magnetotail twist increases away from the planet as the torque exerted by the IMF on the planetary field increases. From these findings we confirm that the tail twist at Mars is likely a result of the direct interaction between the IMF and the planetary crustal fields; however, we find evidence suggesting that the degree of twisting is larger for duskward IMF orientations. This implies that magnetic reconnection on the dayside of Mars, between the IMF and crustal fields, may be favorable under specific IMF configurations.

The Jovian magnetodisk plays an essential role in the dynamics of the Jupiter system by coupling its various components. Here, we investigate the Juno (JADE, JEDI, and MAG) observations of the magnetodisk within 20-80 Jupiter radii ( R J ) in the 0-6 hr local time sector. JADE and JEDI data are combined to generate equatorial plane distributions of density, pressure, temperature, and anisotropy of electrons, protons, and heavy ions. Results show: (a) Heavy ions dominate both the number density and pressure. (b) The number density and pressure of all species decrease with radial distance. (c) The temperature increases for electrons and heavy ions and decreases for protons as radial distance increases. (d) On average, the parallel pressure exceeds the perpendicular pressure for all species. Based on these distributions, we explore the equilibrium and dynamics of the magnetodisk and show that: (a) Radial force balance is primarily achieved between the inward magnetic stress and the outward plasma anisotropy force. (b) An examination of the kappa parameters indicates that electrons, protons, and heavy ions primarily undergo adiabatic motion, magnetic moment diffusion, and stochastic motion, respectively. (c) A radial diffusion coefficient is derived from the radial profile of mass, providing an estimate of the timescale for radial transport from 20 to 80 R J of ∼ 7 hr (d) The total mass ( 5.0 × 1 0 7 kg) and thermal energy ( 3.8 × 1 0 37 eV) of the magnetodisk between 20 and 80 R J are obtained.

Planetary magnetic fields provide a window into the otherwise largely inaccessible dynamics of a planet’s deep interior. In particular, interaction between fluid flow in electrically conducting interior regions and the magnetic field there gives rise to observable secular variation (time dependency) of the externally observed magnetic field. Secular variation of Jupiter’s field has recently been revealed 1–3 and been shown to arise, in part, from an axisymmetric, equatorial jet 2 . Whether this jet is time dependent has not previously been addressed, yet it is of critical importance for understanding the dynamics of the planet’s interior. If steady, it would probably be a manifestation of deep dynamo convective flow (and jets are anticipated as part of that flow 4–9 ) but if time dependent on a timescale much shorter than the convective turnover timescale of several hundred years, it would probably have a different origin. Here we show that the jet has a wavelike fluctuation with a period of roughly 4 years, strongly suggestive of the presence of a torsional oscillation 10 (a cylindrically symmetric oscillating flow about the rotation axis) or a localized Alfvén wave in Jupiter’s metallic hydrogen interior. This opens a pathway towards revealing otherwise hidden aspects of the magnetic field within the metallic hydrogen region and hence constraining the dynamo that generates Jupiter’s magnetic field.

<p>Juno’s highly elliptical polar orbit offers unique in-situ measurements of the electrodynamic interaction between Jupiter and its moon Io. These occur both near Io and near the surface of Jupiter and at distances between. Magnetic field data obtained during multiple traversals of magnetic field lines connected to the orbit of Io reveal remarkably rich and complex current densities along flux tubes connected to Io’s position along its orbit. Using Juno’s many traversals of Io's flux tube (IFT), we derive a model of the strength of the interaction with regards to distance along Io’s extended tail and Io’s position in the plasma torus, illuminating the interaction of Jovian magnetospheric plasma with Io and setting important constraints in the Io-Jupiter interaction.The model is based on an inverse methodology to distribute currents along  the IFT in such a way as to match the magnetic field signature observed during Juno’s traversals of the IFT as well as passages near the IFT. We derive, by means of non-linear optimization, the distribution of current within the IFT (during traversals) as well as the size and morphology of the IFT that best fits the magnetic field observations. We compare our results with observations of the IFT obtained near Io as Voyager 1 passed nearby.</p>

Our knowledge about the fine structure of lightning processes at Jupiter was substantially limited by the time resolution of previous measurements. Recent observations of the Juno mission revealed electromagnetic signals of Jovian rapid whistlers at a cadence of a few lightning discharges per second, comparable to observations of return strokes at Earth. The duration of these discharges was below a few milliseconds and below one millisecond in the case of Jovian dispersed pulses, which were also discovered by Juno. However, it was still uncertain if Jovian lightning processes have the fine structure of steps corresponding to phenomena known from thunderstorms at Earth. Here we show results collected by the Juno Waves instrument during 5 years of measurements at 125-microsecond resolution. We identify radio pulses with typical time separations of one millisecond, which suggest step-like extensions of lightning channels and indicate that Jovian lightning initiation processes are similar to the initiation of intracloud lightning at Earth.

<p>We present plasma observations from a previously unexplored wake region of Ganymede’s magnetosphere obtained by the Jovian Auroral Distributions Experiment (JADE) onboard the Juno spacecraft as it flew by Ganymede on June 7<sup>th</sup>, 2021. This region is highlighted by 1) plasma deflection well downstream of Ganymede's magnetopause, consistent with magnetic field perturbations, 2) plasma composition that is a mix of that in Jupiter’s adjacent plasma sheet or in Ganymede's magnetosphere, and 3) proton, heavy ion and electron distributions that are compressed compared to both adjacent regions. We derive ion and electron velocity distributions, pitch angles, temperatures, and densities inthis newly explored region of Ganymede’s magnetosphere. </p>

Until the arrival of Juno at Jupiter in 2016, the inner electron radiation belt dynamics has been examined from ground-based observations of Jupiter’s Synchrotron Emission (JSE) and theoretical modeling of the relativistic electron population. Simulations of JSE variability on month-to-year timescales only confirm a partial control of the Jovian Electron Radiation Belt (JERB) by large-scale solar-wind-driven particle transport. Juno prime mission and first years of the extended mission provide unique measurements of JSE from within JERB environment allowing us to further address the origins of JSE variability on a timescale of months. In the present work, we use Juno MicroWave Radiometer (MWR) data from mid-2016 to mid-2022 at different wavelengths to support our investigation of the origins of JERB dynamical behavior. Juno/MWR data from NASA Planetary Data System, ground-based observations of Jupiter and simulated Heliospheric Environment (HE) at the giant planet are combined to constrain the modeling of long-term variability of JSE as it would be observed from Earth. The Juno-data constrained trend of JSE at 11.5-cm wavelength is combined with single-dish observations to cover a multi-decade observation period. Using a simulator of JSE that accounts for the influence of physical parameters on jovian electron belts distributions, we present simulations of JSE to discuss the connection between JERB and HE and identify the magnetospheric physical processes (e.g., particle source and transport, interactions with planetary environment) which might have controlled JSE for the period 1962-2022. Acknowledgments: Key data processing, JERB model improvements and simulations of Juno/MWR measurements are carried out at Southwest Research Institute and primarily funded by NASA NFDAP program. This work benefits from collaborations with various Juno instrument teams and also from a larger science community.