Jamey R. Szalay Ph.D.

Associate Research Scholar
Phone: 
609-258-0754
Email Address: 
jszalay AT princeton.edu
Office Location: 
127 Peyton Hall
CV: 
PDF icon 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)

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 has worked 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 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 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.

Research Interests

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

Selected Publications

(See more at Google Scholar)

In Situ Observations Connected to the Io Footprint Tail Aurora (2018), Szalay et al., JGR-Planets

Fig. 1 Szalay et al., 2018

Positions of Juno (circles) during the footprint tail connected measurements for the northern (red) and southern (blue) passes. 

The Juno spacecraft crossed flux tubes connected to the Io footprint tail at low Jovian altitudes on multiple occasions. The transits covered longitudinal separations of approximately 10° to 120° along the footprint tail. Juno’s suite of magnetospheric instruments acquired detailed measurements of the Io footprint tail. Juno observed planetward electron energy fluxes of ~70 mW/m2 near the Io footprint and ~10 mW/m2 farther down the tail, along with correlated, intense electric and magnetic wave signatures, which also decreased down the tail. All observed electron distributions were broad in energy, suggesting a dominantly broadband acceleration process, and did not show any broad inverted-V structure that would be indicative of acceleration by a quasi-static, discrete, parallel potential. Observed waves were primarily below the proton cyclotron frequency, yet identification of a definitive wave mode is elusive. Beyond 40° down the footprint tail, Juno observed depleted upward loss cones, suggesting that the broadband acceleration occurred at distances beyond Juno’s transit distance of 1.3 to 1.7 RJ. For all transits, Juno observed fine structure on scales of approximately tens of kilometers and confirmed independently with electron and wave measurements that a bifurcated tail can intermittently exist.

 

 

Plasma measurements in the Jovian polar region with Juno/JADE (2017), Szalay et al., GRL

Plasma Population in Jupiter's Polar Regions

Heavy ions and electrons at high Jovian latitudes.

Jupiter’s main auroral oval provides a window into the complex magnetospheric dynamics of the Jovian system. The Juno spacecraft entered orbit about Jupiter on 5 July 2016 and carries on board the Auroral Distributions Experiment (JADE) that can directly sample the auroral plasma structures. Here we identify five distinct regimes in the JADE data based on composition/energy boundaries and magnetic field mappings, which exhibit considerable symmetry between the northern and southern passes. These intervals correspond to periods when Juno was connected to the Io torus, inner plasma sheet, middle plasma sheet, outer plasma sheet, and the polar region. When connected to the torus and inner plasma sheet, the heavy ions are consistent with a corotating pickup population. For Juno’s first perijove, we do not find evidence for a broad auroral acceleration region at Jupiter’s main auroral oval for energies below 100 keV.

 

 

 

The Impact Ejecta Environment of Near Earth Asteroids (2016), Szalay & Horanyi , ApJL

Impact Ejecta Distribution for a Near Earth Asteroid

Dust density distribution in the ecliptic frame for grains with a > 0.3 μm above a body with R=10 km. The apex is in the +y direction.

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

Lunar phase averaged cloud densities shown for 45 deg. increments. Each color ring in the densities represent 40 km altitude bins. A peak lunar dust cloud density is observed while the Moon is in its waning gibbous phase.

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.