Jamey R. Szalay, Ph.D.

Position
Research Scholar
Office Phone
Office
171 Broadmead, 103f
CV
Degrees

Ph.D., Physics, University of Colorado Boulder (2015)

M.S., Physics, University of Colorado Boulder (2013)

B.S., Physics, Mathematics, James Madison University (2010)

Bio/Description

Biography

Jamey Szalay is a research scientist interested in space plasma and dust phenomena throughout the solar system. His thesis work focused on impact ejecta measurements from the Lunar Dust Experiment (LDEX) aboard NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) mission at the Moon. He also led the scientific analysis and operations for the Student Dust Counter aboard the New Horizons (NH) mission to Pluto from 2011 to 2015. He works on the Jovian Auroral Distributions Experiment (JADE) aboard NASA's Juno mission to Jupiter, analyzing in-situ plasma data taken in the Jovian polar regions and is particularly interested in the mechanisms responsible for sustaining the bright auroral footprints connected to Jupiter's Galilean moons. His current research also extends measurements of the impact ejecta cloud at the Moon to asteroids throughout the solar system to better understand how their surfaces evolve. He is a Guest Investigator on the Parker Solar Probe mission, studying the evolution of the inner zodiacal cloud via impacts to the spacecraft observed by multiple instruments. He is also interested in the role of interstellar pickup ions (PUI) in our heliosphere's interaction with the interstellar medium and works on data analysis for the Solar Wind Around Pluto (SWAP) instrument aboard NH and the IBEX-Hi instrument aboard NASA's Interstellar Boundary Explorer (IBEX) mission, which both inform on the complex PUI dynamics in our heliosphere. He is also an instrument scientist for the Interstellar Dust Experiment onboard NASA's IMAP mission run out of Princeton.

Research Interests

  • Interplanetary and Interstellar Dust
  • Impact processes and space weathering on airless bodies
  • Jovian auroral phenomena
  • Satellite-magnetosphere interactions
  • Interaction of the Heliosphere with the interstellar medium

Selected Publications

See full publication list at the publications page or at Google Scholar.

Water-Group Pickup Ions From Europa-Genic Neutrals Orbiting Jupiter (2022), Szalay et al., GRL

Jovian magnetosphere
Overview of Jupiter's magnetosphere in the vicinity of the Galilean satellites. H2+ pickup ions (blue) originate from Europa's neutral toroidal cloud (brighter blue near Europa). Io and Europa contribute plasma pickup ions of different compositions to Jupiter's magnetosphere. Alfvén wings connected to the moons due to their interaction with corotating plasma are also shown in gray.

Water-group gas continuously escapes from Jupiter's icy moons to form co-orbiting populations of particles or neutral toroidal clouds. These clouds provide insights into their source moons as they reveal loss processes and compositions of their parent bodies, alter local plasma composition, and act as sources and sinks for magnetospheric particles. We report the first observations of H2+ pickup ions in Jupiter's magnetosphere from 13 to 18 Jovian radii and find a density ratio of H2+/H+ = 8 ± 4%, confirming the presence of a neutral H2 toroidal cloud. Pickup ion densities monotonically decrease radially beyond 13 RJ consistent with an advecting Europa-genic toroidal cloud source. From these observations, we derive a total H2 neutral loss rate from Europa of 1.2 ± 0.7 kg s−1. This provides the most direct estimate of Europa's H2 neutral loss rate to date and underscores the importance of both ion composition and neutral toroidal clouds in understanding satellite- magnetosphere interactions.

 

 

Collisional Evolution of the Inner Zodiacal Cloud (2021), Szalay et al., PSJ

Diverse dust populations in the inner solar system

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 is historically difficult to directly measure and has never been observed for discrete meteoroid streams. After six orbits with Parker Solar Probe (PSP), 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 find the majority of collisional erosion of the zodiacal cloud occurs in the range of 10–20 solar radii and expect this region to also produce the majority of pickup ions due to dust in the inner solar system. A zodiacal erosion rate of at least ~100 kg s−1 and flux of β-meteoroids at 1 au of (0.4–0.8) × 10−4 m−2 s−1 are found to be consistent with the observed impact rates. The β-meteoroids investigated here are not found to be primarily responsible for the inner source of pickup ions, suggesting nanograins susceptible to electromagnetic forces with radii below ~50 nm are the inner source of pickup ions. We expect the peak deposited energy flux to PSP due to dust to increase in subsequent orbits, up to 7 times that experienced during its sixth orbit.

 

Proton Outflow Associated with Jupiter's Auroral Processes (2021), Szalay et al., GRL

Potential structures accelerate ionospheric protons away from Jupiter.

Field-aligned proton beams are a systematic and identifiable feature associated with Jupiter's auroral emissions, transporting 3 ± 2 kg s−1 away from Jupiter's ionosphere. This mass loss occurs at all longitudes sampled by Juno around the southern auroral oval, while the northern hemisphere exhibits upward proton beams predominantly on one portion in System III, near the auroral kink region. These beams are associated with upward inverted-V structures indicative of quasi-static magnetic field- aligned parallel potentials. A lack of bidirectionality indicates these proton populations are pitch-angle and/or energy scattered and incorporated into the magnetospheric charged particle environment. This mechanism is a significant, and potentially dominant, source of protons in Jupiter's middle and outer magnetosphere. If Jupiter's ionosphere is the primary source for protons in the inner magnetosphere, they are likely sourced equatorward of the main emissions and at energies <100 eV.

 

A New Framework to Explain Changes in Io's Footprint Tail Electron Fluxes (2020), Szalay et al., GRL

Precipitating Electron Energy Flux

We analyze precipitating electron fluxes connected to 18 crossings of Io's footprint tail aurora, over altitudes of 0.15 to 1.1 Jovian radii (RJ). 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. These fluxes best fit 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 the majority of parallel electron acceleration sustaining the tail aurora occurs above 1 RJ in altitude. We do not find a correlation between the tail fluxes and the power of the initial Alfvén wave launched from Io. Finally, 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 Impact Ejecta Environment of Near Earth Asteroids (2016), Szalay & Horanyi , ApJL

Impact Ejecta Distribution for a Near Earth Asteroid

Impact ejecta production is a ubiquitous process that occurs on all airless bodies throughout the solar system. Unlike the Moon, which retains a large fraction of its ejecta, asteroids primarily shed their ejecta into the interplanetary dust population. These grains carry valuable information about the chemical compositions of their parent bodies that can be measured via in situ dust detection. Here, we use recent Lunar Atmosphere and Dust Environment Explorer/Lunar Dust Experiment measurements of the lunar dust cloud to calculate the dust ejecta distribution for any airless body near 1 au. We expect this dust distribution to be highly asymmetric, due to non- isotropic impacting fluxes. We predict that flybys near these asteroids would collect many times more dust impacts by transiting the apex side of the body compared to its anti-apex side. While these results are valid for bodies at 1 au, they can be used to qualitatively infer the ejecta environment for all solar-orbiting airless bodies.

 

 

 

 

Annual variation and synodic modulation of the sporadic meteoroid flux to the Moon (2015), Szalay & Horanyi , GRL

 

 

Synodic variation of the lunar ejecta cloud

The Lunar Dust Experiment on board NASA’s Lunar Atmosphere and Dust Environment Explorer discovered a permanently present, asymmetric dust cloud engulfing the Moon, sustained by meteoroid bombardment. It is most dense at 5–8 lunar local time, with a peak density canted sunward. Here we present analysis on the variation of the cloud density during January to April 2014. We find the lunar dust cloud in the Moon’s equatorial plane to be dominantly produced by impacts from three known sporadic meteoroid sources: apex, helion, and antihelion, listed in order of their contribution to ejecta production. The cloud density is also modulated by the Moon’s orbital motion about the Earth, peaking during its waning gibbous phase. These results are complementary to ground-based measurements and indicate the Moon can be used as a very sensitive large area dust detector to characterize the meteoroid environment at 1 AU.