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Europa, the smallest of the Galilean moons, is embedded within Jupiter’s magnetosphere where a rapidly flowing plasma interacts electromagnetically with the moon’s atmosphere and its surface. The magnetic field in the plasma is also affected by Europa’s induced magnetic field in a subsurface conducting layer. On September 29th, 2022 the Juno spacecraft flew by the vicinity of Europa at a distance of ~350 km, and it provided the first in-situ observations since Galileo’s last pass on January 3rd, 2000.In this work, we model the large scale interaction of Jupiter’s magnetospheric plasma with Europa and its atmosphere for the conditions of the Juno flyby. We apply the single fluid MHD PLUTO code based on Mignone et al., [2007], and also employed by Duling et al. [2022] to describe Ganymede’s plasma interaction. Our model accounts for ion-neutral collisions, electron impact ionization, dissociative recombination, and electromagnetic induction in a subsurface water ocean. In particular, we prescribe Europa’s O2 atmosphere with a number of analytical models in which we consider several degrees of asymmetry. Furthermore, we include a tracer description in the model and solve advection equations for the production of the water-group pickup ions H+ and H2+. The simulation results are compared with in-situ measurements provided by the magnetometer and the JADE instrument onboard the Juno spacecraft. Our study is used to further constrain properties of the moon’s atmosphere and to quantify the effects of their variability on the plasma interaction.

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 7th, 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.

The Interstellar Mapping and Acceleration Probe (IMAP) is scheduled to launch in 2025, to be stationed at the Sun-Earth L1 Lagrange point with a combination of 10 in-situ and remote sensing instruments. A primary science goal of IMAP is to improve our understanding of the composition and properties of the local interstellar medium. The local interstellar medium contains plasma, magnetic fields, neutral atoms, cosmic rays, and dust which all influence the heliosphere through interconnected time-dependent and multi-scale processes. The Interstellar Dust Experiment (IDEX) instrument onboard IMAP will measure the flux, size distribution, and composition of interstellar dust particles (ISD), characterizing the inflowing solid matter from the local interstellar medium reaching the inner heliosphere. IDEX will determine whether the composition of the contemporary local interstellar cloud's dust population is consistent with being the feedstock for the formation of the Solar System. In addition to heliospheric science goals, IDEX will also detect the shared pool of interplanetary dust particles (IDP) of cometary and asteroidal origin and determine whether some IDPs preserve unprocessed pre-solar molecular cloud particles or show signatures of processing in the solar system. IDEX will identify primary organic material from asteroids and various cometary families to determine if they share a common source or are formed from distinct reservoirs. IDEX dust detection is based on impact ionization, where elemental and molecular ions are generated in a high-velocity dust impact and analyzed in a time-of-flight (TOF) setup. This talk will discuss the expected scientific results of IDEX that are of primary importance to heliospheric, astrophysical, and planetary sciences. This talk will summarize our current understanding of the ISD and IDP inventory and the expected improvements by the IMAP mission.

Water-group gas continuously escapes from Jupiter’s icy moon Europa in both charged and neutral states. The neutral species form co-orbiting populations of particles, or neutral toroidal clouds, eventually becoming ionized to be incorporated into the Jovian plasma environment. In September 2022, Juno performed a close flyby at ~350 km, an altitude less than the satellite’s radius, allowing it to make direct observations of water-group pickup-ions originating from the moon’s surface. These observations, along with more remote measurements by Juno of Europa-genic water-group pickup ions, provide critical constraints on the evolution and loss processes of Europa’s icy surface. We will present direct observations of water-group pickup-ions from Europa in the context of understanding the breakdown and evolution of Europa’s surface ice.

On 7 June 2021 the Juno spacecraft passed through the Ganymede magnetosphere, with a closest approach altitude of 1046 km. While in the magnetosphere, the Jovian Auroral Distributions Experiment-Ion (JADE-I) sensor observed outflowing ionospheric ions. These are the first in situ observations of the ionospheric ion mass composition. The outflowing ions consist of O2+, O+, H2+, H+, and H3+. Ion densities estimated from the measurements agree with the electron density determined by the Waves instrument to within a factor of 2.5. The light ions appear to be in hydrostatic equilibrium, and the altitude profile is generally symmetric between the inbound and outbound legs of the flyby. H3+ ions are an exception to this, with the ratio of H3+/H2+ being ~a factor 4 lower on the outbound than the inbound leg. The heavy ions have higher densities outbound than inbound. The outflowing flux of light ions peak near closest approach, but the heavy ions peak outbound of the flyby.

Jupiter’s plasma sheet is understood to be dominated by Io-genic material, mostly in various charge states of sulfur and oxygen. This material moves radially away from Jupiter, filling its magnetosphere. The material in the plasma sheet interacts with Europa and Ganymede, which are also sources of magnetospheric pickup ions, mostly in the form of both atomic and molecular hydrogen and oxygen. Juno’s plasma instrument JADE, the Jovian Auroral Distributions Experiment, has provided the first comprehensive in-situ observations of the composition of Jupiter’s plasma sheet with its Time-of-Flight mass-spectrometry capabilities. Here, we present observations of the magnetospheric composition in the Europa-Ganymede region of Jupiter’s magnetosphere. We highlight how Europa-genic material is often present and at times can be the dominant population for certain atomic masses, revealing a more complex and compositionally diverse magnetosphere than previously thought.

The in-ecliptic solar wind influences the boundaries of the Earth’s magnetosphere, e.g., by controlling the distances of the magnetopause and bow shock. The exospheric neutral hydrogen has been measured up to the Moon’s orbit. The charge exchange between the solar wind protons and the neutral geocoronal hydrogen creates an energetic neutral atom (ENA). The field-of-view of the IBEX-Hi instrument onboard the Interstellar Boundary Explorer (IBEX) encompasses various portions of the Earth’s magnetosphere during the year, including the subsolar point. Recently, Sokół et al. 2021 (ApJ 922 250) reported periodic, solar cycle enhancements of the solar wind dynamic pressure. We study the solar cycle evolution of the H ENA flux in the subsolar magnetosheath based on the IBEX measurements. We observed an enhancement of the ENA flux after the maximum of solar activity. We also analyze how the ENA flux varies with the solar wind parameters. We observe positive correlations with the solar wind dynamic pressure in the energy range from 0.7 to 4.3 keV and also opposite variations in correlation coefficients between the ENA flux and the solar wind speed and density.

Water-group gas continuously escapes from Jupiter’s icy moons to form co-orbiting populations of particles, or neutral toroidal clouds. We report the first observations of H2+ pickup ions in Jupiter’s magnetosphere from 13-18 Jovian radii, confirming the presence of a neutral H2 toroidal cloud. Pickup ion densities are consistent with an advecting Europa-genic cloud source. As the observed H2+ ions are originally produced from H2 lost from Europa, the abundance of detected ions allows us to determine that ~1 kg/s of neutral H2 is lost from Europa. Hence, these observations presented here for the first time directly measure ions from a neutral H2 toroidal cloud at Jupiter, prove the cloud provides an additional plasma source in Jupiter’s magnetosphere, and provide the most direct constraints on Europa’s loss of neutral H2 via observations of the neutral toroidal cloud’s primary loss process – pickup ions.

We present a discrete observation of diverse plasma populations and evidence of closed magnetic topology at Jupiter’s polar cap. Two distinct populations of protons are observed over Jupiter’s southern polar cap: a ~1 keV core population and ~1-300 keV dispersive conic population at 6-7 Jovian radii planetocentric distance. We find the 1 keV core protons are likely the seed population for the higher-energy dispersive conics. Transient wave-particle heating in a “pressure-cooker” process is likely responsible for this proton acceleration. The plasma characteristics and composition during this period show Jupiter's polar-most field lines can be topologically closed, with conjugate magnetic footpoints connected to both hemispheres. Finally, these observations demonstrate energetic protons can be accelerated into Jupiter's magnetotail via wave-particle coupling.

The zodiacal cloud is one of the largest structures in the solar system and strongly governed by meteoroid collisions near the Sun. Collisional erosion occurs throughout the zodiacal cloud, yet it has been historically difficult to directly measure. After transiting the inner-most regions of the solar system with Parker Solar Probe (PSP), we find that its dust impact rates are consistent with at least three distinct populations: bound zodiacal dust grains on elliptic orbits (α-meteoroids), unbound β-meteoroids on hyperbolic orbits, and a third population of impactors that may be either direct observations of discrete meteoroid streams or their collisional by-products (“β-streams”). The β-stream from the Geminids meteoroid stream is a favorable candidate for the third impactor population. β-streams of varying intensities are expected to be produced by all meteoroid streams, particularly in the inner solar system, and are a universal phenomenon in all exozodiacal disks. We discuss these recent PSP observations of the dust environment in the very inner solar system, provide constraints on their relative densities and fluxes, and discuss the erosion rate of zodiacal material.These observations are also directly relevant for understanding the impactor and space weathering environment experienced by airless bodies in the inner solar system. Since the discovery of the Moon's asymmetric ejecta cloud, the origin of its sunward-canted density enhancement has not been well understood. Ejecta is produced from β-meteoroids which impact the Moon's sunward side at similar locations to this previously unresolved asymmetry. These small grains are submicron in size, comparable to or smaller than the lunar regolith particles they hit, and can impact the Moon at very high speeds ~100 km s-1. Incorporating β-meteoroid fluxes observed by the Pioneers 8 & 9, Ulysses, and Parker Solar Probe spacecraft as a newly considered impactor source at the Moon, we find β-meteoroid impacts to the lunar surface can explain the sunward asymmetry observed by LADEE/LDEX. We discuss these observations and how this finding suggests β-meteoroids may appreciably contribute to the evolution of other airless surfaces in the inner solar system.

As the closest humanmade object to the sun, the Parker Solar Probe (PSP) is uniquely positioned to study inner heliospheric dust. The PSP/FIELDS instrument suite detects dust via short voltage pulses generated by the plasma clouds formed during hypervelocity dust impacts on the spacecraft. Similar dust detection methods have been used on other missions, including Voyager 1 and 2, STEREO, Wind, Cassini, and Solar Orbiter. In addition to the voltage signatures, about 2% of dust impacts captured by Time Domain Sampler (TDS) burst data on PSP/FIELDS are shown to have magnetic signatures measured by the high-frequency winding of PSP's Search Coil Magnetometer (SCM). While magnetic signatures have previously been detected in laboratory hypervelocity impact experiments, they have not been previously reported in space. The signatures are brief (lasting less than 0.1ms), and are associated with high-amplitude voltage signatures. In this work, we present statistics and case studies of dust impacts with magnetic signatures on PSP. We will discuss the TDS calibration required to interpret the measurements physically, along with potential physical mechanisms for the magnetic signatures. We will also present early modeling efforts and implications for future hypervelocity impact studies.

Jupiter hosts intense auroral activity associated with charged particles precipitating into the planet's atmosphere. The Galilean moons orbiting within the magnetosphere are swept by the magnetic field: the resulting perturbation travels along field lines as Alfven waves, which are able to accelerate electrons towards the planet, producing satellite-induced auroral emissions. These emissions due to the moons, known as footprints, can be detected in various wavelengths (UV, visible, IR) outside the main auroral emission as multiple bright spots followed by footprint tails. Since 2016 the Juno spacecraft orbiting Jupiter has surveyed the polar regions more than 30 times at close distances. Onboard the spacecraft, the Jovian InfraRed Auroral Mapper (JIRAM) is an imager and spectrometer with an L-band imaging filter suited to observe auroral features at unprecedented spatial resolution. JIRAM revealed a rich substructure in the footprint tails of Io, Europa and Ganymede, which appear as a trail of quasi-regularly spaced bright sub-dots whose intensity fades away along the emission trail as the spatial separation from the footprint increases. The fine structure of the Europa and Ganymede footprint tails is reported in this work for the first time. We will also show that the typical distance between subsequent sub-dots is the same for all three moons at JIRAM resolution in both hemispheres. In addition, the sub-dots observed by JIRAM are static in a frame corotating with Jupiter. A feedback mechanism between the ionosphere and the magnetosphere is suggested as a potential candidate to explain the morphology of the footprint tails.

Jupiter’s aurora is complex and dynamic, with a large number of distinct auroral features and regions generated by multiple phenomena. Of these features, Io’s auroral signature is one of the most persistent and identifiable aurora, with a rich observational history spanning decades of remote observations. Since Juno arrived at Jupiter, providing in-situ transits through flux tubes directly connected to Io’s auroral emissions, its diverse set of instruments have revealed an even more complex and dynamic picture of Io’s auroral interaction. In this presentation, we report on Juno observations of precipitating electron fluxes connected to 18 crossings of Io’s footprint tail aurora, over altitudes of 0.15 to 1.1 Jovian radii (RJ). We will highlight how the strength of precipitating electron fluxes is dominantly organized by “Io-Alfvén tail distance”, the angle along Io’s orbit between Io and an Alfvén wave trajectory connected to the tail aurora. We will discuss how these fluxes were best fit with an exponential as a function of down-tail extent with an e-folding distance of 21˚, the acceleration region altitude likely increases down-tail, and most of the parallel electron acceleration sustaining the tail aurora occurs above 1 RJ in altitude. Finally, we will highlight how Juno has likely transited Io’s Main Alfvén Wing fluxtube, observing a characteristically distinct signature with precipitating electron fluxes ~600 mW/m2 and an acceleration region extending as low as 0.4 RJ in altitude.

The Lunar Reconnaissance Orbiter/Lyman Alpha Mapping Project (LAMP) ultraviolet instrument detected a 0.5–2% icy regolith mix on the floor of some of the southern pole permanently shadowed craters of the Moon. We present calculations indicating that most or all of this icy regolith detected by LAMP (sensed to a depth of

Given the compositional diversity of asteroids, and their distribution in space, it is impossible to consider returning samples from each one to establish their origin. However, the velocity and molecular composition of primary minerals, hydrated silicates, and organic materials can be determined by in situ dust detector instruments. Such instruments could sample the cloud of micrometer-scale particles shed by asteroids to provide direct links to known meteorite groups without returning the samples to terrestrial laboratories. We extend models of the measured lunar dust cloud from LADEE to show that the abundance of detectable impact-generated microsamples around asteroids is a function of the parent body radius, heliocentric distance, flyby distance, and speed. We use monte carlo modeling to show that several tens to hundreds of particles, if randomly ejected and detected during a flyby, would be a sufficient number to classify the parent body as an ordinary chondrite, basaltic achondrite, or other class of meteorite. Encountering and measuring microsamples shed from near-earth and main-belt asteroids, coupled with complementary imaging and multispectral measurements, could accomplish a thorough characterization of small, airless bodies., 19 pages, 3 Tables, 10 Figures, accepted May 30, 2019

The two main ultraviolet-signatures resulting from the Io-magnetosphere interaction are the local auroras on Io's atmosphere, and the Io footprints on Jupiter. We study here how Io's daily eclipses ...

The Student Dust Counter (SDC) is an in-situ dust detector aboard the New Horizons spacecraft observing the distribution of interplanetary dust particles (IDPs) with mass > 10 − 12 g or approximately 0.5 µm in radius. New Horizons was launched on January 19th, 2006 and performed a fly-by of the Pluto system on July 14th, 2015. SDC has nearly continuously mapped the dust density distribution along the trajectory of New Horizons, and it continues to operate providing measurements of the IDP in the Edgeworth–Kuiper Belt (EKB). We present results of the dust density distribution from 1 to 38 AU and compare these measurements to existing theoretical models.

Airless bodies in the solar system are continually bombarded by meteoroids, sustaining impact ejecta clouds. While large bodies like the Moon retain a significant fraction of ejecta, small asteroids shed this material into the interplanetary dust complex. Measurements of the lunar impact ejecta cloud found it was sustained by the known sporadic meteoroid sources. Here, we extend those measurements using a model of the IDP environment at 1 au to investigate the structure of an ejecta cloud at an eccentric airless body, asteroid 3200 Phaethon. Due to Phaethon's large eccentricity, its ejecta cloud is highly asymmetric. At 1 au, the cloud is canted towards the asteroid's apex direction and its density varies by five orders of magnitude. Compared to a body in a circular orbit at 1 au, Phaethon's peak ejecta density at 1 au is approximately 30 times higher, largely due to enhanced ejecta production from meteoroids shed from Jupiter Family Comets. Such asymmetric ejecta production suggests Phaethon experiences significantly different meteoroid-specific space weathering processes than a body with a similar semi-major axis on a circular orbit. We estimate impact ejecta processes at Phaethon shed approximately 1 ton per year, which is not sufficient to appreciably contribute to the Geminids meteoroid complex. These estimates most likely represent a lower limit, as Phaethon is expected to have a higher ejecta yield than the Moon. Additionally, we calculate predicted impact counts for a dust detector on close flybys of Phaethon in preparation for the DESTINY+ mission and find the large majority of impacts would be detected on the morning-side sunlit hemisphere. These results suggest eccentric asteroids shed more material than those on near-circular orbits, and are suitable candidates for in-situ dust detection and chemical characterization due to their amplified asymmetric ejecta production.

International audience; Planetary rings are a multifaceted player in the system. Recent advances about Saturn’s rings argue that ring science at the ice giants, with magnetospheric and atmospheric sciences, are essential in advancing our knowledge about solar system evolution, the evolution of the moons and Ocean Worlds, and phenomena observed in the ice giant systems.

International audience; At Jupiter, part of the auroral radio emissions are induced by the Galilean moons Io, Europa and Ganymede. Until now, they have been 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 magnetic flux tubes connected to these moons, or their tail, and gives a direct measure of the characteristics of these decametric moon–induced radio emissions. In this study, we focus on the detection of a radio emission during the crossing of magnetic field lines connected to Ganymede’s tail. Using electromagnetic waves (Juno/Waves) and in-situ electron measurements (Juno/JADE-E), we estimate the flux tube width to be a few 100 km, a radio emission growth rate > 3×10−4, an electron population of energy E = 4 − 15 keV and an emission beaming angle of θ = 76◦ − 83◦ , at a frequency ∼ 1.005 − 1.021 × fce. We also confirmed that radio emission is associated with Ganymede’s down-tail far-ultraviolet emission

The Lunar Environment Monitoring Station (LEMS) is an instrument concept funded by NASA’s Development of Advanced Lunar Instrumentation (DALI) Program, and undergoing maturation at NASA's Goddard Space Flight Center. LEMS has been proposed to the NASA's recent call for Payloads and Research Investigations on the Surface of the Moon (PRISM).LEMS is a compact, autonomous, self-sustaining and long-lasting instrument suite that enables in situ, continuous, long-term monitoring of the lunar exosphere and of the most relevant natural and manmade controlling processes (infall of interplanetary dust particles (IDP), influx of solar wind and magnetospheric particles, EUV irradiation, interior outgassing, disturbances by landers and human surface activities). LEMS can be delivered to the surface of the Moon by crewed or robotic missions. Once deployed (on a deck or directly on the surface), LEMS will operate day and night for a nominal duration of 2 years without requiring any additional support or resources from the carrying asset.LEMS integrates a Mass Spectrometer, a Laser Retro-reflector Array, a Lunar Micrometeoroid Monitor, a Lunar Energetic Ion Analyzer, and a 3-axis Seismometer. These sensors will collect concurrent observations that will lead to a comprehensive, time-resolved, and geographically-localized characterization of the composition and dynamics of volatiles gases in the lunar exosphere as a response to variations in solar forcing, IDP flux, seismicity, and known manmade events. Furthermore, owing to its expected longevity, LEMS will also improve upon the success of the Apollo Passive Seismic Experiment (PSE) by providing a new generation of seismological measurements that will address unanswered questions by the PSEs. These questions include the size and state of the lunar core, homogeneity of the mantle, variation in crustal thickness, the mechanism for deep moonquakes, and the relationship between shallow seismicity and the current tectonic state of the lunar crust.With its complementary and integrated multi-sensors and its autonomous concept of operation, LEMS is a science-enabling investigation that combines capabilities, in a single duplicable instrument package. The duplicative nature of the LEMS design enables a network of stations that focuses on exospheric and geophysical measurements at the Moon to become viable options. Finally, the self-sustaining architecture of LEMS provides a model design of future payloads that can take advantage of more commercial or scientific flight opportunities to the Moon while requiring no further support for operation from their carrying assets.

At Jupiter, part of the auroral radio emissions are controlled by the Galilean moons Io, Europa and Ganymede. Until now, they have been remotely detected using ground-based radio-telescope or electric antenna aboard spacecraft. The polar trajectory of the Juno orbiter leads to cross the magnetic flux tube connected to these moons, or their tail, and gives a direct in-situ measurements of the characteristics of these decametric moon induced radio emissions (such as the electron population, size of the source, and beaming angle and growth rate of the emission). In this study, we focus on the crossing of the Ganymede flux tube. The study of Juno/JADE-E and Juno/Waves data leads to an estimated source size of a few 100s km, an electron population of energy E= 8±2 keV and an emission beaming angle of θ= 80±2° from the magnetic field lines. Finally, this crossing of a decametric radio emission induced by a moon brings us new constrains on the Cyclotron Maser Instability process

Observations by the JUNO spacecraft revealed energetic, bidirectional particle populations with broadband energy distributions in the high-latitude region of Jupiter. These measurements indicate that an acceleration mechanism of stochastic nature plays a dominant role for the generation of the intense main auroral oval. In our current work, we investigate the acceleration of energetic electrons and protons recently observed by JUNO in the Io flux tube wake near Jupiter. We try to infer on the relevant physical acceleration process by considering a resonant as well as a non-resonant wave-particle interaction mechanism, both based on Alfven waves. We focus on necessary temporal scales to drive these mechanisms efficiently and also on the released wave energy by means of the transported Poynting flux along the flux tube.

Introduction. We present the scientific potential for using an Interstellar Probe (ISP) spacecraft traveling to > 500 AU from the Sun to study the dust in the solar system's debris disks and the nearby ISM, as well as to map the surface of a flyby KBO and study the Cosmic Background Light (CBL). Figure 1 – Interstellar Probe Explorer payload at its design goal location of 1000 AU with respect to the planets, the heliopause, Alpha Centauri, and the Oort Cloud. Discussion. The solar system is known to house two planetesimal belts, the inner Jupiter Family Comet (JFC) + Asteroid belt and the outer Edgeworth-Kuiper Belt (EKB), and at least one debris cloud, the Zodiacal Cloud, sourced by planetesimal collisions and comet evaporative sublimation. However, these are poorly understood in toto because we live inside of them. It is not understood well how much dust is produced from the EKB since the near-Sun comet contributions dominate the inner cloud and only New Horizons (NH) has ever flown a dust counter through the EKB. New estimates from NH put the EKB disk mass at at 30 – 40 times the inner disk mass [1]. Better understanding EKB dust production will improve our estimates of the number of EKB bodies, especially the smallest ones, and their dynamical collisional state. For the innermost Zodiacal cloud, questions remain concerning its overall shape and orientation with respect to the invariable plane - these are not explainable from perturbations caused by the known planets alone. Imaging Studies. Using new technologies and passively cooled detectors, a suitable low system size/mass/power VISNIR spectrometer/FIR imager + 10 cm class primary has been specified using a CubeSat study baseline design [2]. The VISNIR spectrometer could provide maps of the cloud's dust particle size and composition, while FIR imagery would map the dust cloud's density. 3-D cloud mapping would occur during flythrough via tomographic inversion, and via lookback imaging once the s/c is beyond 200 AU. The lookback imaging will allow ISP to measure for the 1st time in history the entire extent of the Zodiacal Cloud, and determine whether its inner JFC/asteroidal & outer KBO parts connect smoothly, as predicted by Stark & Kuchner [3-4] and detected by Piquette, Poppe et al. [5-8] (Figs. 2-3). This would also allow direct comparison of the solar system’s debris disks with those observed around other nearby stars, and test theories that suggest that our solar system is planet rich but dust-poor [9]. Figure 2 – Predicted dust cloud morphologies arising from solar system JFC (JFC) & Oort Cloud (OCC) comets & Kuiper Belt (EKB) sources. (Top) Looking down on the solar system. (Bottom) Looking through the plane of the solar system. After [1]. Looking back towards the Sun from >100 AU, ISP will perform deep searches for the presence of rings and dust clouds around discrete sources, like Planet X, the Haumea family of icy collisional fragments, the rings of the Centaur Chariklo, or dust emitted from spallation off the larger KBOs. The same instrument will map the surfaces of KBOs encountered along the way. Measurement of the cloud’s total brightness will allow removal of its signal from near-Earth CBL measurements looking at all the starlight ever formed in the Universe, and the same instrument will return its own remote CBL measurements. Figure 3 – NH in situ measurements (black data pts) and predicted dust flux contributions (colored curves) for the solar system’s debris disks [1,8]. Measured PIONEER 10 dust fluxes are in the upper left corner of the plot, so the predicted crossover at ~10 AU from JFC dominated to EKB dominated is seen. ISP will help us determine if another crossover from EKB dominated to OCC dominated occurs at ~100 AU, and if the EKB dust is ice, rock, & organics rich like KBOs and comets. First Ever Outer Solar System In Situ Dust Characterization. ISP can also carry the first ever in situ dust chemical analyzer past Saturn. Based on the Europa Clipper SUDA instrument [10], it will compositionally and directionally characterize the solar system’s dust clouds and will help isolate their sources, like the rocky asteroidal dust bands and the icy Haumea family fragments. Using measured dust particle masses and velocities, dust input & loss rates from these sources will be derived. Direct dust sampling will return the first ever in situ chemical analysis of EKB dust, the first ever in situ sampling of dust beyond 200 AU, and provide calibrated ground truth for cloud models produced from our imagery. It should also resolve the tension between the expected makeup of inflowing ISM microdust as determined by remote sensing and the mesasured ISM dust component found at Jupiter and Saturn by Galileo, Ulysses, and Cassini ([11] & Figure 4). Understanding a G2V’s Astropause ISM Bowshock. At the outermost solar system edges, the role dust plays in shaping and energizing the heliosphere’s boundary with the local galactic medium is almost completely unknown. Estimates range up to 1/3 of the heliopause and heliosheath energy density is in the dust. Current heliopause/sheath models do not allow for dusty plasma physics because the dust component is so poorly known. We do know that submicron sized dust is streaming into the solar system's ram direction through the local ISM, and the large deficit between remote sensing models of local ISM dust and ISM dust measured inside the solar system suggests a large amount of energy is involved in diverting much of the impinging dust around the edges of the solar system. Figure 4 – Disconnect between the nearby ISM dust size distribution predicted from remote sensing measurements (blue) and ISM dust counts measured inside the solar system (red). After [11]. References: [1] Poppe+2019, ApJLett881, L12 [2] Zemcov+2019, AASMeeting#233, id.#171.06 [3] Stark&Kuchner 2009, ApJ707, 543 [4] Stark&Kuchner 2010, AJ140, 1007 [5] Poppe+2010, Geophys.Res.Lett.37, L11101 [6] Poppe&Horányi 2012, Geophys.Res.Lett. 39, 1 [7] Poppe2016, Icarus264, 369 [8] Piquette+2019, Icarus321, 116 [9] Greaves&Wyatt 2010, MNRAS404, 1944 [10] Kempf+2014, EPSCAbstracts9, EPSC2014-229 [11] Weingartner&Draine, ApJ548, 296; Draine&Hensley 2016, ApJ831, 59

International audience; We report the first in situ observations of electron measurements at a Europa footprint tail (FPT) crossing in the auroral region. During its 12th science perijove pass, Juno crossed magnetic field lines connected to Europa's FPT. We find that electrons in the range ~0.4 to ~25 keV, with a characteristic energy of 3.6 ± 0.5 keV, precipitate into Jupiter's atmosphere to create the footprint aurora. The energy flux peaks at ~36 mW/m2, while the peak ultraviolet (UV) brightness is estimated at 37 kR. We estimate the peak electron density and temperature to be 17.3 cm-3 and 1.8 ± 0.1 keV, respectively. Using magnetic flux shell mapping, we estimate that the radial width of the interaction at Europa's orbit spans roughly 3.6 ± 1.0 Europa radii. In contrast to typical Io FPT crossings, the instrument background caused by penetrating energetic radiation (> ~5-10 MeV electrons) increased during the Europa FPT crossing.

We present Juno observations between 03:00 to 06:00 UT on day-of-year 86, 2017 that link electrons in Jupiter's polar magnetosphere to images of transient, enhanced UV emissions in Jupiter's dawn a...

International audience; This work examines the variation of interplanetary dust count rates and directionality during the first three solar encounters made by the Parker Solar Probe spacecraft, covering distances between 0.65 au (∼140 solar radii, RS) and 0.16 au (∼35 RS). Dust detections are made by the FIELDS instrument via plasma clouds, produced by impact ionization of dust grains on spacecraft surfaces and resultant spacecraft potential perturbations. Dust count rates and inferred densities are found to vary by ∼50% between the three solar encounters (∼5 months per orbit), with most of the variation concentrated below 0.23 au (∼50RS). Dust count rates and directionality, as well as the encounter-to-encounter variability in both quantities are found to be consistent with β-meteoroids: dust grains exiting the solar system on hyperbolic trajectories. Interpretation of the the dust count rate data and the dust directionality data independently suggest (i) that the β-meteoroid source region is more complex than preliminary models suggest, and (ii) that the primary β-meteoroid source region is approximately located between 10 and 30 solar radii from the Sun. These data offer important clues as to the location and geometry of the β-meteoroid source region, and consequently clues about the collisional and sublimation processing of interplanetary dust grains near the Sun.

The Interstellar Boundary Explorer (IBEX) mission provides global energetic neutral atom (ENA) observations from the heliosphere and the Earth's magnetosphere, including spatial, temporal, and energy information. IBEX views the magnetosphere from the sides and almost always perpendicular to noon‐midnight plane. We report the first ENA images of the energization process in the Earth's ion foreshock and magnetosheath regions. We show ENA flux and spectral images of the dayside magnetosphere with significant energization of ENA plasma sources (above ~2.7 keV) in the region magnetically connected to the Earth's bow shock (BS) in its quasi‐parallel configuration of the interplanetary magnetic field (IMF). We also show that the ion energization increases gradually with decreasing IMF‐BS angle, suggesting more efficient suprathermal ion acceleration deeper in the quasi‐parallel foreshock., Key Points We present the first remote‐sensing global images of ion energization in the Earth's foreshockWe provide ion energization profile as a function of bow shock obliquityWe quantify the difference of energization in magnetosheath and its magnetically connected counterpart in the upstream foreshock

International audience; Jupiter's ultraviolet (UV) aurorae, the most powerful and intense in the solar system, are caused by energetic electrons precipitating from the magnetosphere into the atmosphere where they excite the molecular hydrogen. Previous studies focused on case analyses and/or greater than 30-keV energy electrons. Here for the first time we provide a comprehensive evaluation of Jovian auroral electron characteristics over the entire relevant range of energies (~100 eV to ~1 MeV). The focus is on the first eight perijoves providing a coarse but complete System III view of the northern and southern auroral regions with corresponding UV observations. The latest magnetic field model JRM09 with a current sheet model is used to map Juno's magnetic foot point onto the UV images and relate the electron measurements to the UV features. We find a recurring pattern where the 3- to 30-keV electron energy flux peaks in a region just equatorward of the main emission. The region corresponds to a minimum of the electron characteristic energy (J. Outside that region, the >100-keV electrons contribute to most (>~70-80%) of the total downward energy flux and the characteristic energy is usually around 100 keV or higher. We examine the UV brightness per incident energy flux as a function of characteristic energy and compare it to expectations from a model.

Jupiter’s ultraviolet (UV) aurora, the most powerful and intense in the solar system, is caused by energetic electrons precipitating from the magnetosphere into the atmosphere where they excite the molecular hydrogen. Electrons from ~50 eV to ~100 keV are characterized over the auroral regions by the Jovian Auroral Distributions Experiment (JADE) on Juno. Investigating the characteristics of electron distributions at these energies is critical for understanding the source population for the electrons that produce Jupiter’s UV aurora and the mechanisms that accelerated them to keV and MeV energies. In this study, we present a survey of electron distributions and moments derived from JADE in Jupiter’s polar magnetosphere. We quantify the electron properties (e.g. density and temperature) and explore similarities and differences in their distributions over several Juno perijove passes, focusing on regions near the main emission.

Our understanding of the lunar dust exosphere is based on NASA’s Lunar Atmosphere and Dust Environment Explorer. Its findings provide a unique opportunity to map the composition of the lunar surface from orbit and identify regions that are rich in volatiles, providing opportunities for future in situ resource utilization (ISRU), which is a key element in establishing human habitats on the Moon. The expected availability of water ice, and other volatiles, in Permanently Shadowed Regions (PSR) makes the lunar poles of prime interest. However, the relative strength of the various sources, sinks, and transport mechanisms of water into and out of PSRs remain largely unknown. The quantitative characterization of the temporal and spatial variability of the influx of IDPs to the polar regions of the Moon is critical to the understanding the evolution of volatiles in PSRs. A dust instrument onboard a polar orbiting lunar spacecraft could make fundamental measurements to assess the availability and accessibility of water ice in PSRs. Water is thought to be continually delivered to the Moon through geological timescales by water-bearing comets and asteroids and produced continuously in situ by the impacts of solar wind protons of oxygen-rich minerals on the surface. IDPs are an unlikely source of water due to their long UV exposure in the inner solar system, but their high-speed impacts can mobilize secondary ejecta dust particles, atoms and molecules, some with high-enough speed to escape the Moon. Other surface processes that can lead to mobilization, transport and loss of water molecules and other volatiles include solar heating, photochemical processes, and solar wind sputtering. Since the efficiency of these are reduced in PSRs, dust impacts remain the dominant process to dictate the evolution of volatiles in PSRs.The continually present dust ejecta cloud was observed by LADEE/LDEX. A more capable dust instrument, in addition to the size and speed of an impacting particle, can also measure the composition of secondary ejecta particles, resulting in a surface composition map with a spatial resolution comparable to the height of the spacecraft.This talk will describe the available instrumentation, its testing and calibration using the SSERVI /IMPACT dust accelerator facility at the University of Colorado, Boulder, and conclude with the recognition that a polar-orbiting spacecraft could directly sample lunar ejecta, providing the critical link between IDP bombardment and the evolution of water ice in PSRs.

The Parker Solar Probe (PSP) mission has completed 4 encounters through the solar corona significantly closer to the Sun than previous measurements. While PSP does not have a dedicated dust detector, measurements by the various instruments can provide insights into the dust environment in the inner heliosphere. Throughout the PSP orbit, interplanetary dust is impacting the spacecraft. Three-dimensional reconstructions of FIELDS observations show that the rate and direction of the dust impacts varies throughout the PSP orbit. During the encounter WISPR also finds the rate of impacts changes through the encounter period, but also a decrease in the intensity of the light scattered by the dust particles. The smooth decrease in the WISPR intensity beginning at about 0.1 AU is consistent with the production of Beta-meteroids seen by FIELDS. In this presentation, we will discuss the observations from the FIELDS and WISPR instruments and discuss initial models of the dust environment. The authors acknowledge support from the NASA Parker Solar Probe program.

The zodiacal cloud in the inner solar system undergoes continual evolution, as its dust grains are collisionally ground and sublimated into smaller and smaller sizes. Sufficiently small (~