Lucas Liuzzo

University of California, Berkeley | UCB

The magnetometer investigation of the Galileo mission used the phenomenon of magnetic induction to produce the most compelling evidence that subsurface oceans exist within our solar system. Although there is high certainty that the induced field measured at Europa is attributed to a global‐scale subsurface ocean, there is still uncertainty around t...

We investigate the emission of energetic neutral atoms (ENAs) from the magnetosphere‐atmosphere interactions at Europa and Callisto that may be observed by an ENA imaging instrument. To do so, we combine the draped electromagnetic fields from the AIKEF hybrid model with a tracing tool for the energetic magnetospheric parent ions. Using a realistic...

In this study, we show that non‐thermal collisions can play a significant role in shaping Europa's exospheric structure. Collisions between radiolytically produced O2 ${\mathrm{O}}_{2}$ and the O produced via electron impact dissociation of O2 ${\mathrm{O}}_{2}$ affect the exospheric structure and escape rates. Specifically, O + O2 ${\mathrm{O}}_{2...

In this study, we show that non-thermal collisions can play a significant role in shaping Europa's exospheric structure. Collisions between radiolytically produced O2 and the O produced via electron impact dissociation of O2 play a significant role in affecting the exospheric structure and escape rates. Specifically, O+O2 collisions lead to the pro...

Plain Language Summary The Moon is located within the tail of Earth's magnetosphere during one‐third of its orbit. Although the strong terrestrial magnetic field prevents high‐energy particles from reaching Earth's surface, the Moon does not receive the same protection when it is within the terrestrial magnetotail. Instead, we show that the high‐en...

Plain Language Summary The magnetized planets of the solar system are known to possess a population of high‐energy, orbiting electrons that are sustained for extended timescales. By comparison, Ganymede, the only moon in the solar system confirmed to have its own permanent magnetic field, should also retain a similar population of trapped particles...

Jupiter’s largest moon Ganymede has its own intrinsic magnetic field, which forms a magnetosphere that is embedded within Jupiter’s corotating magnetospheric plasma. This scenario has been shown to lead to complex ion precipitation patterns that have been connected to heterogeneous space weathering across Ganymede’s surface. We present the first si...

This study focuses on constraining the role that Callisto's perturbed electromagnetic environment had on energetic charged particle signatures observed during the Galileo mission. To do so, we compare data from the Energetic Particle Detector (EPD) obtained during four close encounters of the moon with a model framework that combines hybrid simulat...

Plain Language Summary Located within Jupiter's magnetosphere, the small Galilean moon Europa is continuously exposed to a flow of magnetized plasma, traveling at a relative velocity of about 100 km/s. The deflection of this plasma around Europa generates perturbations to Jupiter's magnetic field, as observed for the first time in two decades durin...

To study the emission of energetic neutral atoms (ENAs) at Titan, we have developed a novel model that takes into account a spacecraft detector's limited field of view and traces energetic magnetospheric particles backward in time. ENAs are generated by charge exchange between Titan's atmospheric neutrals and energetic magnetospheric ions. By traci...

Using a hybrid model (kinetic ions, fluid electrons), we provide context for plasma and magnetic field observations from Juno's PJ34 flyby of Ganymede on 07 June 2021. We consider five model configurations that successively increase the complexity of Ganymede's atmosphere and ionosphere by including additional particle species and ionization mechan...

We analyze the emission of energetic neutral atom (ENA) flux from charge exchange between Jovian magnetospheric ions and the atmospheres of Callisto and Europa. For this purpose, we combine the draped electromagnetic fields from a hybrid plasma model with a particle tracing tool for the energetic ions. We determine the ENA flux through a concentric...

Observations of Callisto's atmosphere have indicated an O2 component should exist, but the evolution from its initial source to its inferred steady‐state abundance is not well understood. Herein we constrain the production of O2 via radiolysis within Callisto's exposed ice patches and determine the corresponding O2 column density. To do so, for the...

We calculate the time‐varying spatial distribution of energetic magnetospheric electron influx onto Europa's surface by combining a hybrid model of the moon's draped electromagnetic environment with a relativistic particle tracer. We generate maps of the energetic electron influx patterns at four distinct locations of Europa relative to the center...

Plain Language Summary During two thirds of its orbit, the Moon is located outside of Earth's magnetosphere. At these locations, the lunar surface is exposed to a variety of charged particles including (low‐energy) solar wind plasma and (high‐energy) Solar Energetic Particles (SEPs), the latter of which are responsible for weathering and chemically...

The JEDI instrument made measurements of energetic charged particles near Ganymede during a close encounter with that moon. Here we find ion flux levels are similar close to Ganymede itself but outside its magnetosphere and on near wake and open field lines. But energetic electron flux levels are more than a factor of 2 lower on polar and near‐wake...

This study investigates how Callisto's perturbed electromagnetic environment—generated by the moon's interaction with the low‐energy Jovian magnetospheric plasma—affects the dynamics of high‐energy ions and electrons. We constrain how these perturbed fields influence the energetic particle fluxes deposited onto the top of Callisto's atmosphere betw...

We combine the electromagnetic fields from a hybrid plasma model with a particle tracing tool to study the spatial distribution of energetic neutral atoms (ENAs) emitted from Titan's atmosphere when the moon is exposed to different magnetospheric upstream regimes. These ENAs are generated when energetic magnetospheric ions undergo charge exchange w...

The magnetosphere of Jupiter harbors the most extreme fluxes of MeV electrons in the solar system and therefore provides a testbed of choice to understand the origin, transport, acceleration, and loss of energetic electrons in planetary magnetospheres. Along this objective, the Pitch Angle Distribution (PAD) of energetic electrons may reveal signat...

The JUpiter ICy moons Explorer (JUICE) of the European Space Agency will investigate Jupiter and its icy moons Europa, Ganymede, and Callisto, with the aim to better understand the origin and evolution of our Solar System and the emergence of habitable worlds around gas giants. The Particle Environment Package (PEP) on board JUICE is designed to me...

This study investigates the lunar plasma environment when embedded within Earth's magnetotail. We use data from 10 years of tail crossings by the Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon's Interaction with the Sun (ARTEMIS) spacecraft in orbit around the Moon. We separate the plasma environments by magnetosheath‐like,...

Many moons in the solar system are thought to potentially harbor hidden oceans based on the features observed at their surfaces. However, the magnetic induction signatures measured in the vicinity of these moons provide the most compelling evidence for the presence of a subsurface ocean, specifically for the Jovian moons Europa and Callisto. Interp...

For the entire ion energy range observed at Europa, we calculate spatially resolved maps of the surface sputtering rates of H2O, O2, and H2 from impacts by magnetospheric ions. We use the perturbed electromagnetic fields from a hybrid model of Europa’s plasma interaction, along with a particle‐tracing tool, to calculate the trajectories of magnetos...

A prominent feature of the interaction between a planetary moon and its magnetospheric environment is the formation of a wake cavity in the downstream hemisphere, characterized by a significant decrease of the incident plasma density. Using an analytical model of Triton's sub‐Alfvénic interaction with Neptune's magnetosphere, we demonstrate that th...

In this paper we present ab initio 3D Monte-Carlo simulations of Ganymede’s surface sputtered and sublimated H2O exosphere. As inputs, we include surface water content maps and temperature distribution maps based on Galileo and Very Large Telescope (VLT) observations. For plasma precipitation, we use hybrid model results for thermal H+ and O+, ener...

The tilt between Neptune’s magnetic and rotational axes, along with Triton’s orbital obliquity, causes a strong time variability of the moon’s local electromagnetic environment. To constrain Triton’s interaction with the ambient magnetospheric plasma, we apply a hybrid (kinetic ions, fluid electrons) model including the moon’s ionosphere and induce...

Plain Language Summary Since the Moon lacks a thick atmosphere, both external plasmas and interplanetary micrometeoroids directly interact with the lunar surface. Consequently, the lunar surface builds up a static electric potential that balances all electric currents. NASA's Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon's...

We develop an analytical model of the Alfvén wings generated by the interaction between a moon's ionosphere and its sub‐Alfvénic magnetospheric environment. Our approach takes into account a realistic representation of the ionospheric Pedersen conductance profile that typically reaches a local minimum above the moon's poles and maximizes along the...

Plain Language Summary Earth's Moon is exposed to a wide range of particle and magnetic field environments during its 29.5‐day orbit. When outside of Earth's magnetosphere, the Moon experiences the rapidly flowing, dense solar wind plasma. However, for a few days each month, the terrestrial magnetosphere shields the Moon from the solar wind; instea...

We combine the electromagnetic fields from a hybrid model with a particle‐tracing code to calculate the time‐varying spatial distribution of magnetospheric ion flux onto the surface of Jupiter’s moon Europa. The electromagnetic fields at Europa are perturbed by the sub‐alfvénic interaction of the moon’s ionosphere and induced dipole with the magnet...

From orbit, the visibility of Titan’s surface is limited to a handful of narrow spectral windows in the near-infrared (near-IR), primarily from the absorption of methane gas. This has limited the ability to identify specific compounds on the surface—to date Titan’s bulk surface composition remains unknown. Further, understanding of the surface comp...

From orbit, the visibility of Titan's surface is limited to a handful of narrow spectral windows in the near-infrared (near-IR), primarily from the absorption of methane gas. This has limited the ability to identify specific compounds on the surface -- to date Titan's bulk surface composition remains unknown. Further, understanding of the surface c...

We constrain the diagnostic potential of ion energy spectrograms to identify signatures of water vapor plumes in the thermal plasma environment of Jupiter's moon Europa. For this purpose, we apply a hybrid model of Europa's Alfvénic plasma interaction to calculate the perturbations of the flow and the electromagnetic fields near the moon for variou...

This study examines the bombardment of energetic magnetospheric electrons onto Ganymede as a function of Jovian magnetic latitude. We use the output from a three‐dimensional, hybrid model to constrain features of the electromagnetic environment during the G1, G8, and G28 Galileo encounters when Ganymede was located far above, within, or far below J...

The moon Dione orbits Saturn at 6.2 Saturn radii RS deep in the Kronian magnetosphere. In situ studies of the moon‐magnetosphere interaction processes near Dione were possible with the Cassini/Huygens mission which flew by close to Dione five times at distances between 99 and 516 km. In addition, Cassini crossed Dione's L‐shell more than 400 times...

The goal of our study is to present a systematic modeling framework for the identification of water vapor plumes in plasma and magnetic field data from spacecraft flybys of Europa. In particular, we determine the degree to which different plume configurations can be obscured by the interaction of Jupiter's magnetospheric plasma with Europa's induce...

We model the dynamics of energetic magnetospheric ions in the perturbed electromagnetic fields near Jupiter's moon Europa. The inhomogeneities in the fields near Europa are generated by the induced dipole field from the moon's subsurface ocean as well as the Alfvénic plasma interaction with its ionosphere and induced field. Inhomogeneities in Europ...

We examine the dynamics of energetic magnetospheric electrons exposed to the highly perturbed and asymmetric plasma environment of Jupiter’s moon Callisto. The interaction of the (nearly) corotating magnetospheric plasma with Callisto’s ionosphere and induced dipole locally generates intense electromagnetic pileup and draping signatures which vary...

Plain Language Summary Observations by the Hubble Space Telescope have revealed the presence of water vapor plumes at Jupiter's icy moon Europa. However, in contrast to the Enceladus plume, the occurrence of plumes at Europa seems to be a transient phenomenon. The mechanism governing the times and locations of these emissions is still unknown. In a...

Using hybrid simulations and analytical calculations, we investigate the observable magnetic perturbations during the 12 planned Callisto flybys of the JUpiter ICy moons Explorer mission. During four of these encounters, Callisto will be embedded within Jupiter's magnetospheric current sheet. In these cases, Callisto's Alfvén wings and ramside magn...

We examine the dynamics of energetic magnetospheric ions in the highly perturbed and asymmetric electromagnetic environment of the Jovian moon Callisto. The Alfvénic interaction of the (nearly) corotating magnetospheric plasma with Callisto's ionosphere and induced dipole generates electromagnetic field perturbations near the moon, the structure of...

Mercury is the closest orbiting planet around the sun and is therefore embedded in an intensive and highly varying solar wind. In-situ data from the MESSENGER spacecraft of the plasma environment near Mercury indicates that a coronal mass ejection (CME) passed the planet on 23 November 2011 over the span of the 12 h MESSENGER orbit. Slavin et al. (...

We apply a hybrid (kinetic ions, fluid electrons) simulation model to study Pluto's plasma environment during the New Horizons encounter on 14 July 2015. We show that Pluto's plasma interaction is dominated by significant north-south asymmetries, driven by large pickup ion gyroradii on the order of 200 Pluto radii. The transition region from the am...

We apply a combination of analytical modeling, hybrid simulations, and data analysis techniques to provide a comprehensive study of magnetometer data from four Galileo flybys of Callisto (C21, C22, C23, C30) that have never been discussed in the literature before. Callisto's distance to the center of Jupiter's magnetospheric current sheet varied co...

We apply a combination of data analysis and hybrid modeling to study Callisto's interaction with Jupiter's magnetosphere during the Galileo C10 flyby on 17 September 1997. This encounter took place while Callisto was located near the center of Jupiter's current sheet. Therefore, induction in Callisto's subsurface ocean and magnetospheric field line...

The interaction between Callisto's atmosphere and ionosphere with the surrounding magnetospheric environment is analyzed by applying a hybrid simulation code, in which the ions are treated as particles and the electrons are treated as a fluid. Callisto is unique among the Galilean satellites in its interaction with the ambient magnetospheric plasma...

This study investigates the processes that lead to the detection of split signatures in ion density during several crossings of the Cassini spacecraft through Titan's mid-range plasma tail (T9, T63, and T75). During each of these flybys, the Cassini Plasma Spectrometer detected Titan's ionospheric ion population twice; i.e., the spacecraft passed t...

Winds in the thermosphere are highly important for transporting mass, momentum, and energy over the globe. In the high latitude region, observations show that ion and neutral motions are strongly coupled when the aurora is present, but the coupling is less evident when there is no aurora. In this study, we investigate the ability of the Global Iono...