A5025887062- Astro and Planetary Science
- Planetary Science and Exploration
- Ionosphere and magnetosphere dynamics
- Geomagnetism and Paleomagnetism Studies
- Solar and Space Plasma Dynamics
- Space Science and Extraterrestrial Life
- Spacecraft Design and Technology
- Earthquake Detection and Analysis
- Space Exploration and Technology
- Space exploration and regulation
- Scientific Research and Discoveries
- Spacecraft and Cryogenic Technologies
- Geophysics and Gravity Measurements
- Space Satellite Systems and Control
- Superconducting Materials and Applications
- Distributed and Parallel Computing Systems
- Methane Hydrates and Related Phenomena
- Magnetic Bearings and Levitation Dynamics
- Magnetic confinement fusion research
- Spaceflight effects on biology
- Geophysical and Geoelectrical Methods
- Magnetic Properties and Applications
- Electromagnetic Launch and Propulsion Technology
Catholic University of America
2020-2024
Goddard Space Flight Center
2019-2024
University of America
2020-2023
University of Maryland, Baltimore County
2019-2020
University of Maryland, Baltimore
2019
University of Michigan
2012-2019
Charles River Laboratories (Netherlands)
2015-2016
John Wiley & Sons (United States)
2015
Laboratory for Atmospheric and Space Physics
2012
University of Colorado Boulder
2012
Abstract The structure of Mercury's dayside magnetosphere is investigated during three extreme solar wind dynamic pressure events. Two were the result coronal mass ejections (CMEs), and one was from a high‐speed stream (HSS). inferred pressures for these events are ~ 45 to 65 nPa. CME produced thick, low‐ β (where ratio plasma thermal magnetic pressure) depletion layers high reconnection rates 0.1–0.2, despite small shear angles across magnetopause only 27 60°. For events, brief, 1–2 s long...
Abstract Electrons are accelerated to high, nonthermal energies during explosive energy-release events in space, such as magnetic reconnection. However, the properties and acceleration mechanisms of relativistic electrons directly associated with reconnection X-line not well understood. This study utilizes Magnetospheric Multiscale (MMS) measurements analyze flux spectral features subrelativistic (∼80–560 keV) a event Earth’s magnetotail. provided unique opportunity measure energized by MMS...
Abstract MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) measurements taken during passes over Mercury's dayside hemisphere indicate that on four occasions the spacecraft remained in magnetosheath even though it reached altitudes below 300 km. During these disappearing magnetosphere (DDM) events, did not encounter magnetopause until was at very high magnetic latitudes, ~66 to 80°. These DDM events stand out with respect their extremely solar wind dynamic pressures,...
Abstract We perform a statistical study of flux ropes and reconnection fronts based on MErcury Surface, Space ENviroment, GEochemistry, Ranging (MESSENGER) magnetic field plasma observations to the implications for spatial distribution sites in Mercury's near magnetotail. The results show important differences temporal distributions as compared Earth. have surveyed sheet crossings between −2 R M −3 downtail from planet, i.e., location Near‐Mercury Neutral Line (NMNL). Plasma sheets were...
Abstract The structure, X‐line location, and magnetohydrodynamic (MHD) stress balance of Mercury's magnetotail were examined between −2.6 < X MSM −1.4 R M using MErcury Surface, Space ENvironment, GEochemistry, Ranging (MESSENGER) measurements from 319 central plasma sheet (CPS) crossings. mean β in the CPS calculated MESSENGER data is ~ 6. magnetic field was southward (i.e., tailward X‐line) 2–18% time. Extrapolation downtail variations B Z indicates an average location at −3 . Modeling...
Abstract We identify and examine all MErcury Surface Space ENvironment, GEochemistry, Ranging (MESSENGER) crossings of Mercury's dayside magnetopause with magnetospheric field intensities ≥300 nT. The eight such events, which occurred under highly compressed magnetosphere conditions, are analyzed in the identical manner utilized by Slavin et al. (2014, https://doi.org/10.1002/2014JA020319 ). results suggest that events represent highest solar wind dynamic pressures for MESSENGER's orbit...
Abstract We present the first observation of a flux rope at Saturn's dayside magnetopause. This is an important result because it shows that Saturnian magnetopause conducive to multiple X‐line reconnection and generation. Minimum variance analysis magnetic signature consistent with rope. The observations were well fitted constant‐ α force‐free model. radius content are estimated be 4600–8300 km 0.2–0.8 MWb, respectively. Cassini also observed five traveling compression regions (remote...
Abstract MErcury Surface, Space ENviroment, GEochemistry, and Ranging (MESSENGER) magnetic field plasma measurements taken during crossings of Mercury's magnetotail from 2011 to 2014 have been examined for evidence substorms. A total 26 events were found which an Earth‐like growth phase was followed by clear near‐tail expansion signatures. During the phase, just as at Earth, thinning sheet increase intensity in lobe are observed, but fractional could be ∼3 5 times that Earth. The average...
Abstract Mercury's flux transfer event (FTE) showers are dayside magnetopause crossings accompanied by large numbers (≥10) of magnetic ropes (FRs). These shower events common, occurring during 52% (1,953/3,748) the analyzed crossings. Shower observed with shear angles (θ) from 0° to 180° across and magnetosheath plasma β 0.1 10 but most prevalent for high θ low . Individual FR duration correlates positively, while spacing negatively, content core field intensity correlate negatively , they...
Abstract This study analyzes 25 ion‐scale flux ropes in the Magnetospheric Multiscale (MMS) observations to determine their structures. The high temporal and spatial resolution MMS measurements enable application of multispacecraft techniques ropes. Flux are identified as quasi‐one‐dimensional (quasi‐1‐D) when they retain features reconnecting current sheets; that is, magnetic field gradient is predominantly northward or southward, quasi‐2‐D exhibit circular cross sections; gradients plane...
The Martian magnetotail exhibits a highly twisted configuration, shifting in response to changes polarity of the interplanetary magnetic field's (IMF) dawn-dusk (BY) component. Here, we analyze ∼6000 MAVEN orbits quantify degree twisting (θTwist) and assess variations as function (a) strong planetary crustal field location, (b) Mars season, (c) downtail distance. results demonstrate that θTwist is larger for duskward (+BY) IMF orientation majority time. This preference likely due local...
This paper summarizes the Seven Sisters solar wind mission concept and outstanding science questions motivating objectives. The includes seven individual spacecraft designed to uncover fundamental physical processes in provides up ≈ 2 days of advanced space weather warnings for 550 Earth during mission. will collect critical measurements thermal suprathermal plasma magnetic fields, utilizing, first time, Venus–Sun Lagrange points. multi-spacecraft configuration makes it possible distinguish...
Analysis and interpretation of observations from the MESSENGER spacecraft in orbit about Mercury require knowledge solar wind “forcing” parameters. We have utilized Wang‐Sheeley‐Arge (WSA)‐ENLIL modeling tool order to calculate values interplanetary magnetic field (IMF) strength ( B ), velocity V ) density n ram pressure (~ nV 2 cross‐magnetosphere electric × Alfvén Mach number M A other derived quantities relevance for wind‐magnetosphere interactions. compared upstream IMF measurements see...
Abstract We analyzed MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) magnetic field plasma measurements taken during 319 crossings of Mercury's cross‐tail current sheet. found that the measured B Z in sheet is higher on dawnside than duskside by a factor ≈3 asymmetry decreases with downtail distance. This result consistent expectations based upon MHD stress balance. The fields threading more stretched have beta those dawnside, where they are less stretched....
Abstract Mercury possesses a miniature yet dynamic magnetosphere driven primarily by magnetic reconnection occurring regularly at the magnetopause and in magnetotail. Using newly developed Magnetohydrodynamics with Adaptively Embedded Particle‐in‐Cell (MHD‐AEPIC) model coupled planetary interior, we have performed series of global simulations range upstream conditions to study detail kinetic signatures, asymmetries, flux transfer events (FTEs) associated Mercury's dayside reconnection. By...
Magnetic reconnection plays a fundamental role in transporting energy, momentum, and plasma from the solar wind to magnetosphere-ionosphere system. During an IMF southward turning, magnetopause X-line forms near magnetic equator region is considered drive dayside convection However, how azimuthal size of flows at ionosphere relate each other, what mechanisms control flow remain unclear. In this study, we use global ideal MHD simulation address question using event during turning. The results...
Previous studies on the interaction of Mars&#8217; un-magnetized space environment with solar wind have shown that structural morphology hybrid magnetosphere and plasma dynamical processes occurring within are strongly driven by its conditions. This unique is highly complex during quiet periods, let alone extreme conditions such as encounter CMEs or other transient structures. emphasizes importance accurate knowledge upstream when any spacecraft inside magnetosphere. However, all...
The complex and variable interaction between the conducting Martian ionosphere incoming solar wind causes draping of interplanetary magnetic field (IMF) lines around Mars, giving rise to a weak induced magnetosphere (IM) despite planet&#8217;s lack global intrinsic field. is result ionospheric currents nearly perpetual dynamic feature topology. This IMF can be observed at crossing pile-up plasma boundary (MPB), defined by characteristic increase in magnitude attenuation fluctuations,...
Abstract In this study, we use the magnetic field data measured by MErcury Surface, Space ENvironment, GEochemistry, and Ranging from 2011 to 2015 investigate average morphology of Mercury's magnetotail in down tail 0–3 R M ( = 2,440 km, radius). It is found that Mercury has a terrestrial‐like magnetotail; structure beyond 1.5 stretched significantly with typical lobe 50 nT. A cross‐tail current sheet separating antiparallel lines lobes present equatorial plane. The width north‐south...
Abstract The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft while in orbit about Mercury observed highly localized, ~3‐s‐long reductions the dayside magnetospheric magnetic field, with amplitudes up to 90% of ambient intensity. These field depressions are termed cusp filaments because they were from just poleward midlatitudes, i.e., ~55° 85°N. We analyzed 345 high‐ low‐altitude identified MESSENGER data determine their physical properties. Minimum...
Abstract We present the first observation of fast plasma flows in Mercury's magnetotail. Mercury experiences substorm activity phenomenologically similar to Earth's; however, field‐of‐view limitations Fast Imaging Plasma Spectrometer (FIPS) prevent instrument from detecting sheet. Although FIPS measures incomplete distributions, subsonic impart an asymmetry on partial distribution, even if flow directions are outside field view. combine observations 387 intervals containing magnetic...
Abstract Mercury possesses a miniature but dynamic magnetosphere driven primarily by the solar wind through magnetic reconnection. A prominent feature of dayside magnetopause reconnection that has been frequently observed is flux transfer events (FTEs), which are thought to be an important player in driving global convection at Mercury. Using BATSRUS Hall magnetohydrodynamics model with coupled planetary interior, we have conducted series simulations investigate generation and...
Abstract The energization and heating processes for protons in the near‐Mercury tail are examined with MErcury Surface, Space ENvironment, GEochemistry, Ranging (MESSENGER) observations. In a case study, suprathermal proton particle flux (STPF) temperature observed to be clearly enhanced during substorm dipolarizations, indicating processes. STPF distributions central plasma sheets display dawn‐dusk asymmetries, higher values dawnside sheet, i.e., postmidnight, than duskside, premidnight....
Abstract An automated method was applied to identify magnetotail flux rope encounters in MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) magnetometer data. The identified significant deflections of the north‐south component magnetic field coincident with enhancements total or dawn‐dusk component. Two hundred forty‐eight ropes are that possess well‐defined minimum variance analysis (MVA) coordinate systems, clear rotations field. Approximately 30% can be well...