A5026789101- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Earthquake Detection and Analysis
- Astro and Planetary Science
- Planetary Science and Exploration
- Space Science and Extraterrestrial Life
- Space exploration and regulation
- Geophysics and Gravity Measurements
- Atmospheric Ozone and Climate
- Spacecraft Design and Technology
- Laser-induced spectroscopy and plasma
- Space Satellite Systems and Control
- Space Exploration and Technology
- Plasma Diagnostics and Applications
- Meteorological Phenomena and Simulations
- Radiation Therapy and Dosimetry
- Mass Spectrometry Techniques and Applications
- Atomic and Subatomic Physics Research
- Magnetic confinement fusion research
- GNSS positioning and interference
- Lightning and Electromagnetic Phenomena
- Electron and X-Ray Spectroscopy Techniques
- Dust and Plasma Wave Phenomena
- Spaceflight effects on biology
University of Michigan
2016-2025
University of Alaska Fairbanks
2000-2021
Charles River Laboratories (Netherlands)
2015-2019
West Virginia University
2016
Michigan United
2002-2014
University of Sheffield
2014
University of Science and Technology of China
2014
Heliophysics
2014
Goddard Space Flight Center
2014
John Wiley & Sons (United States)
2014
Abstract Atmospheres of exoplanets in the habitable zones around active young G-K-M stars are subject to extreme X-ray and EUV (XUV) fluxes from their host that can initiate atmospheric erosion. Atmospheric loss affects exoplanetary habitability terms surface water inventory, pressure, efficiency greenhouse warming, dosage UV irradiation. Thermal escape models suggest atmospheres K-M should undergo massive hydrogen escape, while heavier species including oxygen will accumulate forming an...
Three storms are examined to determine the contribution Dst * index from symmetric and asymmetric (partial) components of ring current. The (September 24–25, 1998, October 18–19, May 14–15, 1997) all have a similar solar wind trigger (an initial shock followed by coronal mass ejection with southward interplanetary magnetic field) placement in cycle (rising phase). near‐Earth ion distribution function is simulated for each storm using kinetic transport model. use McIlwain magnetospheric...
The interaction of the solar wind and Earth's magnetosphere is complex phenomenology very different for dominated by interplanetary coronal mass ejections (ICMEs) compared to corotating regions (CIRs). We perform a superposed epoch study effects ICME‐ CIR‐dominated upon storm‐time plasma at geosynchronous orbit using data from magnetospheric analyzer (MPA) instruments on board seven Los Alamos National Laboratory (LANL) satellites. Using 78 ICME events 32 CIR events, we examine electron ion...
Abstract The Mars Atmosphere and Volatile Evolution mission has obtained comprehensive particle magnetic field measurements. Solar Wind Electron Analyzer provides electron energy‐pitch angle distributions along the spacecraft trajectory that can be used to infer topology. This study presents pitch angle‐resolved energy shape parameters distinguish photoelectrons from solar wind electrons, which we use deduce Martian topology connectivity dayside ionosphere. Magnetic in environment is mapped...
Abstract The basic structure and dynamics of the primary electric current systems in Earth's magnetosphere are presented discussed. In geophysics, word is used to describe flow mass from one location another, its analog a charge place another. An associated with magnetic field, they combine internally generated dipolar field form topology magnetosphere. concept an reviewed compared other approaches investigate physics implications understanding magnetospheric discussed, including paths...
The magnetospheric physics research community uses a broad array of quantitative data-model comparison methods (metrics) when conducting their investigations. It is often the case, though, that any particular study will only use one or two metrics, with most common being Pearson correlation coefficient and root mean square error (RMSE). Because metrics are designed to test specific aspect relationship, limiting reduces physical insights can be gleaned from analysis, restricting possible...
MHD-based global space weather models have mostly been developed and maintained at academic institutions. While the "free spirit" approach of academia enables rapid emergence testing new ideas methods, lack long-term stability support makes this arrangement very challenging. This paper describes a successful example university-based group, Center Space Environment Modeling (CSEM) University Michigan, that Weather Framework (SWMF) its core element, BATS-R-US extended MHD code. It took quarter...
A time‐dependent kinetic model is used to investigate the relative importance of various mechanisms in early phase decay rate ring current. It found that, for both solar maximum storm June 4–7, 1991 and especially minimum September 24–27, 1998, convective drift loss out dayside magnetopause dominant process removing current particles during initial recovery. During 1998 storm, outflow losses outpaced charge exchange by a factor ten.
We present a comprehensive study of plasma properties at geosynchronous orbit for electron and ion energies between ∼1 eV ∼45 keV, 1990 2001. The variations temperature density are analyzed as functions local time, magnetospheric convection strength, the strength ring current. Various parameters derived from calculated to elucidate temporal spatial location delivery sheet material into inner magnetosphere. find that proton densities greatest in dawn region periods highest current strength....
Low‐latitude ionospheric and near‐Earth magnetospheric electric fields are calculated from model results of the storm time asymmetric ring current. These generated subauroral field‐aligned currents out ionosphere in midnight sector into on dayside. The balance divergence current, which is dominant component current during main phase early recovery magnetic storms. basic shape potential pattern described, both magnetosphere. It found that intense injection events can create differences up to...
Abstract Geomagnetic indices are convenient quantities that distill the complicated physics of some region or aspect near‐Earth space into a single parameter. Most best‐known calculated from ground‐based magnetometer data sets, such as Dst, SYM‐H, Kp, AE, AL, and PC. Many models have been created predict values these indices, often using solar wind measurements upstream Earth input variables to calculation. This document reviews current state geomagnetic methods used assess their ability...
Electric currents flowing through near-Earth space ($\textit{R}$ $\leq$12 $\mathit{R}_{E}$) can support a highly distorted magnetic field topology, changing particle drift paths and therefore having nonlinear feedback on the themselves. A number of current systems exist in magnetosphere, most commonly defined as (1) dayside magnetopause Chapman-Ferraro currents, (2) Birkeland field-aligned with high latitude "region 1" lower-latitude 2" connected to partial ring current, (3) magnetotail (4)...
Abstract The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission samples the ionosphere down to altitudes of ∼150 km over a wide range local times solar zenith angles. On 5 January 2015 (Orbit 520) when spacecraft was in darkness at high northern latitudes (solar angle, SZA >120°; latitude >60°), Solar Wind Electron Analyzer (SWEA) instrument observed photoelectrons below 200 km. Such observations imply presence closed crustal magnetic field loops that cross terminator extend...
The 4–6 June 1991 magnetic storm, which occurred during solar maximum conditions, is analyzed to investigate two observed features of storms that are not completely understood: (1) the mass‐dependent decay ring current early recovery phase and (2) role preconditioning in multistep development. A kinetic drift‐loss model, driven by dynamic fluxes at nightside outer boundary, was used simulate this storm interval. strong partial developed persisted throughout main phases. majority ions make...
This paper addresses the question of particular characteristics and causes intense space storms. We focus on several unresolved issues, which are critical to storm research often nourish open disputes: extent interplanetary driving, role substorms in dynamics through acceleration particles ring current energies, identity lead agent fast decay right after maximum cause two‐phase recovery storms, global morphology storm‐time current, predictability Space physics has been driven by more or less...
We report a newly created highly parallelized global test particle model for resolving the pickup oxygen ion distribution around Mars. The background magnetic and convection electric fields are calculated using three‐dimensional multispecies magnetohydrodynamic model, which includes effect of Martian crustal field. In addition to photo‐ionization, charge exchange collisions solar wind electron impact ionization included generation. most novel feature our is that more than one billion...
Abstract The transport and acceleration of low‐energy electrons (50–250 keV) from the plasma sheet to geostationary orbit were investigated. Two moderate storm events, which occurred on 6–7 November 1997 12–14 June 2005, modeled using Inner Magnetosphere Particle Transport Acceleration model (IMPTAM) with boundary set at 10 R E in sheet. output IMPTAM was compared observed electron fluxes four energy ranges (50–225 measured by Synchronous Orbit Analyzer instrument onboard Los Alamos National...
Abstract Using the Helium Oxygen Proton Electron (HOPE) and Electric Field Waves (EFW) instruments from Van Allen Probes, we explored relationship between electron energy fluxes in eV keV ranges spacecraft surface charging. We present statistical results on charging within geosynchronous orbit by L MLT. An algorithm to extract H + line HOPE instrument data was developed better explore intense events. Also, this study how potential relates number density, pressure, temperature, thermal...
One of the definitions space weather describes it as time-varying environment that may be hazardous to technological systems in and/or on ground endanger human health or life. The ring current has its contributions effects, both terms particles, ions and electrons, which constitute it, magnetic electric fields produced modified by at space. We address main aspects effects from starting with brief review discovery physical processes Dst-index predictions storm occurrence based it. Special...
Ionospheric conductance is a crucial factor in regulating the closure of magnetospheric field-aligned currents through ionosphere as Hall and Pedersen currents. Despite its importance predictive investigations magnetosphere - coupling, estimation ionospheric auroral region precarious most global first-principles based models. This impreciseness estimating impedes both our understanding capabilities magnetosphere-ionosphere system during extreme space weather events. In this article, we...