A5023904336- Astro and Planetary Science
- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Planetary Science and Exploration
- Earthquake Detection and Analysis
- Space Exploration and Technology
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Space Satellite Systems and Control
- Stellar, planetary, and galactic studies
- Laser-induced spectroscopy and plasma
- Magnetic confinement fusion research
- Plasma Diagnostics and Applications
- Isotope Analysis in Ecology
- Nuclear Physics and Applications
- Atomic and Subatomic Physics Research
- Photocathodes and Microchannel Plates
- Atmospheric Ozone and Climate
- Spacecraft and Cryogenic Technologies
- Electron and X-Ray Spectroscopy Techniques
- Particle accelerators and beam dynamics
- High-pressure geophysics and materials
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
Johns Hopkins University Applied Physics Laboratory
2016-2025
Johns Hopkins University
2014-2024
Allentown Public Library
2017-2024
University of Colorado Boulder
2007-2023
Marshall University
2023
Mentor
2023
University of Iowa
2023
Southwest Research Institute
2007-2023
National Aeronautics and Space Administration
2023
The University of Texas at San Antonio
2022
The NASA Radiation Belt Storm Probes (RBSP) mission addresses how populations of high energy charged particles are created, vary, and evolve in space environments, specifically within Earth’s magnetically trapped radiation belts. RBSP, with a nominal launch date August 2012, comprises two spacecraft making situ measurements for at least 2 years nearly the same highly elliptical, low inclination orbits (1.1×5.8 RE, 10∘). slightly different so that 1 laps other about every 2.5 months, allowing...
Magnetic reconnection is a fundamental physical process in plasmas whereby stored magnetic energy converted into heat and kinetic of charged particles. Reconnection occurs many astrophysical plasma environments laboratory plasmas. Using measurements with very high time resolution, NASA's Magnetospheric Multiscale (MMS) mission has found direct evidence for electron demagnetization acceleration at sites along the sunward boundary Earth's magnetosphere where interplanetary field reconnects...
Spectra, integral moments, and composition (H, He, O, S) of energetic ions (50 keV to 50 MeV) are presented for selected Jupiter magnetospheric positions near the equator between radial distances ∼6 ∼46 radii ( R J ), as revealed by analysis Galileo Energetic Particle Detector data. These characteristics then used basis interpreting modeling reported signatures ion/neutral gas interactions within Jupiter's inner magnetosphere, particularly neutral atom emissions measured during Cassini...
The local time position of the low-energy substorm-injected plasma boundary in dusk to midnight region magnetosphere as observed by geostationary satellite ATS 5 is found be correlated with interpolated Kp index. Considering resolution Kp, correlation quite close but dependent on season. An estimate overall shape and within this a function using fit our winter data conjunction presented Carpenter (1967) concerning Kp-related radial positioning plasmapause postmidnight region. This analysis...
The Jupiter Energetic Particle Detector Instruments (JEDI) on the Juno polar-orbiting, atmosphere-skimming, mission to will coordinate with several other space physics instruments spacecraft characterize and understand environment of Jupiter’s polar regions, specifically generation powerful aurora. JEDI comprises 3 nearly-identical measures at minimum energy, angle, ion composition distributions ions energies from H:20 keV O: 50 >1 MeV, energy angle distribution electrons <40 >500 keV. Each...
The Magnetospheric Imaging Instrument (MIMI) onboard the Cassini spacecraft observed saturnian magnetosphere from January 2004 until Saturn orbit insertion (SOI) on 1 July 2004. MIMI sensors frequent energetic particle activity in interplanetary space for several months before SOI. When imaging sensor was switched to its neutral atom (ENA) operating mode 20 February 2004, at approximately 10(3) times Saturn's radius RS (0.43 astronomical units), a weak but persistent signal magnetosphere....
The ATS−6 geostationary satellite has observed many examples of propagating, electromagnetic Alfv́en/ion cyclotron waves in both plasma particle and magnetic field data. These have been viewed predominantly near the afternoon dusk regions earth’s magnetosphere with normalized frequencies (ω/ΩH+) ranging between 0.05 0.5. Viewed from an average geomagnetic latitude +10°, only to propagate northward, suggesting that they are generated within equatorial or minimum ‖B‖ regions. Two wave events...
An X‐ray detector has been flown on‐board a NASA F‐106 jet into thunderstorms. We have concluded that significant quantities of 3 to >12 keV X‐rays are produced within thunderstorm clouds which support lightning discharge activity. It is inferred the bremsstrahlung radiation emitted from energetic electrons accelerated through run‐away processes. suggested and supported structures responsible for acceleration strong double‐layers by very high current densities attributed discharges.
A more precise and definitive relation between diffuse auroras their particle source region was determined by examining simultaneously the observations at geosynchronous orbit auroral display as well electron precipitations near its field line conjugate observed polar‐orbiting DMSP 32 satellite. It is found that spectral shape differential fluxes of precipitated electrons are very similar, sometimes almost identical, to those trapped plasma sheet located in magnetospheric equator. The...
To address factors dictating similarities and differences between solar system radiation belts, we present comparisons relativistic electron belt spectra of all five strongly magnetized planets: Earth, Jupiter, Saturn, Uranus, Neptune. We choose observed with the highest intensities near ∼1 MeV compare them against expectations based on so‐called Kennel‐Petschek limit (KP). For evaluating KP limit, begin a recently published formulation then add several refinements our own. Specifically,...
Magnetic reconnection is an energy conversion process that occurs in many astrophysical contexts including Earth's magnetosphere, where the can be investigated situ by spacecraft. On 11 July 2017, four Magnetospheric Multiscale spacecraft encountered a site magnetotail, involves symmetric inflow conditions. The electron-scale plasma measurements revealed (i) super-Alfvénic electron jets reaching 15,000 kilometers per second; (ii) meandering motion and acceleration electric field, producing...
The Energetic Particle Detector (EPD) Investigation is one of 5 fields-and-particles investigations on the Magnetospheric Multiscale (MMS) mission. MMS comprises 4 spacecraft flying in close formation highly elliptical, near-Earth-equatorial orbits targeting understanding fundamental physics important physical process called magnetic reconnection using Earth’s magnetosphere as a plasma laboratory. EPD two sensor types, Ion Spectrometer (EIS) with instrument each spacecraft, and Fly’s Eye...
The Juno spacecraft acquired direct observations of the jovian magnetosphere and auroral emissions from a vantage point above poles. Juno's capture orbit spanned bow shock to planet, providing magnetic field, charged particle, wave phenomena context for passage over poles traverse Jupiter's hazardous inner radiation belts. energetic particle plasma detectors measured electrons precipitating in polar regions, exciting intense aurorae, observed simultaneously by ultraviolet infrared imaging...
The Energetic Particle Detector (EPD) Investigation is one of five particles and fields investigations on the Magnetospheric Multiscale (MMS) mission. This mission consists four satellites operating in close proximity elliptical, low-inclination orbits, focused upon fundamental physics magnetic reconnection. investigation aboard MMS spacecraft two instrument designs, EIS (Energetic Ion Spectrometer) FEEPS (Fly’s Eye Electron Proton Spectrometer). present paper describes from an engineering...
Abstract Energetic particle transport into the inner magnetosphere during geomagnetic storms is responsible for significant plasma pressure enhancement, which driver of large‐scale currents that control global electrodynamics within magnetosphere‐ionosphere system. Therefore, understanding from tail deep near‐Earth magnetosphere, as well energization processes associated with this transport, essential a comprehensive knowledge space environment. During main phase storm on 17 March 2013...
Abstract Juno obtained unique low‐altitude space environment measurements over Jupiter's poles on 27 August 2016. Here Jupiter Energetic‐particle Detector Instrument observations are presented for electrons (25–800 keV) and protons (10–1500 keV). We analyze magnetic field‐aligned electron angular beams expected auroral regions that were sometimes symmetric (bidirectional) but more often strongly asymmetric. Included variable surprisingly persistent upward, monodirectional emerging from what...
Abstract Based on high‐resolution measurements from NASA's Magnetospheric Multiscale mission, we present the dynamics of electrons associated with current systems observed near diffusion region magnetic reconnection at Earth's magnetopause. Using pitch angle distributions (PAD) and curvature analysis, demonstrate occurrence electron scattering in curved field down to energies 20 eV. We show that occurs closer sheet as energy decreases. The inflowing electrons, field‐aligned electrostatic...
Abstract We investigate spatial and temporal scales at which wave‐particle interaction of Alfvén waves occurs in Jupiter's magnetosphere. consider electrons, protons, oxygen ions study the regions along magnetic flux tubes where plasma is densest, that is, equatorial sheet, most dilute, above ionosphere, auroral particle acceleration expected to occur. find within a dipole L‐shell roughly 30, electron inertial length scale region dominating scale, suggesting Landau damping kinetic can play...
Abstract Previous Juno mission event studies revealed powerful electron and ion acceleration, to 100s of kiloelectron volts higher, at low altitudes over Jupiter's main aurora polar cap (PC; poleward the aurora). Here we examine 30–1200 keV JEDI‐instrument particle data from first 16 orbits determine how common, persistent, repeatable, ordered these processes are. For PC regions, find (1) upward angle beams, sometimes extending megaelectron volt energies, are persistently present in...
The Magnetospheric Imaging Instrument (MIMI) Ion and Neutral Camera (INCA) on the Cassini spacecraft has recorded abrupt increases in energetic neutral atom flux coming from general direction of Saturn's magnetotail. These bursts ion activity tail are well correlated with enhancements Saturn kilometric radiation. Given similarities between these events substorm Earth, including their dependence interplanetary conditions, we conclude that Earth‐like substorms occur within magnetosphere.