A5028141629- Ionosphere and magnetosphere dynamics
- Earthquake Detection and Analysis
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Atmospheric Ozone and Climate
- Lightning and Electromagnetic Phenomena
- Astrophysics and Cosmic Phenomena
- Geophysics and Sensor Technology
- earthquake and tectonic studies
- Gamma-ray bursts and supernovae
- Soil Moisture and Remote Sensing
- Reservoir Engineering and Simulation Methods
- Pulsars and Gravitational Waves Research
- Radiation Detection and Scintillator Technologies
- Laser-Plasma Interactions and Diagnostics
- GNSS positioning and interference
- High-pressure geophysics and materials
- Hydrogen embrittlement and corrosion behaviors in metals
- Advanced Optical Sensing Technologies
- Geophysical and Geoelectrical Methods
- Forecasting Techniques and Applications
- Geophysics and Gravity Measurements
- Precipitation Measurement and Analysis
- Atomic and Molecular Physics
- Microstructure and Mechanical Properties of Steels
Goddard Space Flight Center
2022-2024
University of America
2022-2024
Catholic University of America
2022-2024
Johns Hopkins University Applied Physics Laboratory
2023-2024
Boston University
2017-2020
National Institute of Technology Calicut
2020
Abstract We analyze the drivers, distribution, and properties of relativistic electron precipitation (REP) detected near midnight by Polar Orbiting Environmental Satellites (POES) Meteorological Operational (MetOp) satellites, critical for understanding radiation belt losses nightside atmospheric energy input. REP is either driven wave‐particle interactions (isolated within outer belt), or current sheet scattering (CSS; with dispersion), a combination two. evaluate L‐MLT distribution...
Quiet, discrete auroral arcs are an important and fundamental consequence of solar wind-magnetosphere interaction. We summarize the current standing observations such arcs. review basic characteristics arcs, including occurrence in time space, lifetimes, width length, as well brightness, energy magnetospheric electrons responsible for optical emission. briefly discuss connection between single multiple The acceleration by high-altitude electric potential structure is reviewed, together with...
Abstract The extreme substorm event on 5 April 2010 ( THEMIS AL = −2,700 nT, called supersubstorm) was investigated to examine its driving processes, the aurora current system responsible for supersubstorm, and magnetosphere‐ionosphere‐thermosphere (M‐I‐T) responses. An interplanetary shock created aurora, but not a direct driver of supersubstorm onset. Instead, with large southward IMF strengthened growth phase substantially larger ionosphere currents, more rapid equatorward motion auroral...
Simultaneous solar wind measurements from the monitors, WIND and ACE, differ due to spatial temporal structure of wind. Correlation studies that use these as input may infer an incorrect correlation uncertainties arising this structure, especially at extreme rare values. In particular, regression analysis will lead a function whose slope is biased towards mean value measurement parameter. This article demonstrates bias by comparing simultaneous ACE measurements. A non-linear between them...
Solar wind measurements at the L1 Lagrange point provide an uncertain estimate of electromagnetic and plasma parameters driving magnetosphere, as these are taken far from critical magnetopause reconnection site. This uncertainty leads to underestimating Earth's response extreme space weather. Previous research has observed that with increasing solar strength, appears saturate, rather than scale proportionally. Over past four decades, numerous theoretical explanations for this saturation...
Earth’s magnetosphere is an unstable system. We observe this in many aspects of the system, for example, substorms. A key indicator state system amount open magnetic flux and rate at which it changing. These measures are intimately tied to driving (i.e. dayside reconnection) but also, response nightside reconnection). When they become imbalanced, extraordinary phenomena such as substorms can dominate magnetospheric dynamics. Understanding when how these imbalances occur therefore a...
Abstract On 26 March 2008, simultaneous measurements of a large substorm were made using the Poker Flat Incoherent Scatter Radar, Time History Events and Macroscale Interactions during Substorm (THEMIS) spacecraft, all sky cameras. After onset, electron precipitation reached energies ≳100 keV leading to intense D region ionization. Identifying source energetic has been challenge because lack quantitative magnetically conjugate loss cone electrons. In this study, we use maximum entropy...
Abstract It has been proposed (Chimonas & Hines, , https://doi.org/10.1029/JA075i004p00875) that a total solar eclipse should generate internal gravity waves (GWs) manifest as traveling ionospheric disturbances (TIDs) at heights. Zhang et al. ( https://doi.org/10.1002/2017GL076054) recently reported observations of electron density perturbations trailing the region maximum obscuration, claiming results first unambiguous evidences for eclipse‐induced bow waves. We present evidence showing...
Abstract We investigate a significant duskside ionospheric density modulation in the Pc5 frequency band and related spatial structures during storm on 28 May 2017. take advantage of 3‐D observations by PFISR simultaneous magnetospheric situ observations. Inversion suggests that pulsations modulated precipitating electrons over broad range energies (~5–500 keV). Such strong electron precipitation likely caused rate ~8 Pedersen Hall conductances to vary rapidly peaked at ~70–100 S. The...
Abstract We present observations that show structured diffuse aurora (SDA) correlated with electron precipitation directly from the outer boundary of radiation belt. The SDA maps to nightside transition region (∼9–12 R E ) in magnetic‐equatorial plane during a substorm growth phase. energy flux 100‐ 300‐keV electrons lost belt is ∼0.4 mW/m 2 , which comparable dropouts >100 keV magnetic storms. latitudinal dispersion energetic observed ionosphere more equatorward suggests nonadiabatic...
Many studies of solar-wind coupling with the magnetosphere depend on properties solar wind impacting magnetosphere. Our ability to estimate these relies heavily spacecraft measurements at first Lagrangian point (L1), far upstream Earth. best estimates are made by time-shifting observations bow shock nose. Hence, we uncertain parameters that affect Apart from instrumental errors, uncertainty stems many simplifying assumptions ignore inherent variability L1 (e.g., meso-scale structures,...
Extreme space weather events occur during intervals of strong solar wind electric fields. Curiously these intervals, their impact on measures the Earth's response, like polar cap index, is not as high expected. Theorists have put forward a host explanations for this saturation effect, but there no consensus. Here we show that merely perception created by uncertainty in measurements, especially measurement times. Correcting reveals extreme elicit ~300% larger than previously thought....
Energetic electron precipitation (EEP) from the radiation belts into Earth’s atmosphere leads to several profound effects (e.g., enhancement of ionospheric conductivity, possible acceleration ozone destruction processes). An accurate quantification energy input and ionization due EEP is still lacking instrument limitations low-Earth-orbit satellites capable detecting EEP. The deployment ELFIN (Electron Losses Fields InvestigatioN) CubeSats marks a new era observations with an improved...
The spatial distribution of energetic protons contributes towards the understanding magnetospheric dynamics. Based upon 17 years Cluster/RAPID observations, we have derived machine learning-based models to predict proton intensities at energies from 28 1,885 keV in 3D terrestrial magnetosphere radial distances between 6 and 22 RE. We used satellite location indices for solar, solar wind geomagnetic activity as predictors. results demonstrate that neural network (multi-layer perceptron...
Abstract Energetic electron precipitation (EEP) from the radiation belts into Earth's atmosphere leads to several profound effects (e.g., enhancement of ionospheric conductivity, possible acceleration ozone destruction processes). An accurate quantification energy input and ionization due EEP is still lacking instrument limitations low‐Earth‐orbit satellites capable detecting EEP. The deployment Electron Losses Fields InvestigatioN (ELFIN) CubeSats marks a new era observations with an...
Whitepaper #369 in the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033. Main topics: basic research. Additional planetary magnetospheres; ground-based missions/projects; space-based system science.
Abstract One of the major and unfortunately unforeseen sources background for current generation X-ray telescopes are few tens to hundreds keV (soft) protons concentrated by mirrors. such telescope is European Space Agency’s (ESA) Multi-Mirror Mission (XMM-Newton). Its observing time lost due contamination about 40%. This loss affects all broad science goals this observatory, ranging from cosmology astrophysics neutron stars black holes. The soft-proton could dramatically impact future large...
As we attempt to infer a system's response external driving from measurements, random errors in the measurement of drivers can lead us mistakenly non-linear response. In particular, are likely underestimate during extreme and rare conditions due uncertainty drivers. We demonstrate this phenomenon for space weather its impact on Earth's magnetosphere, where measurements solar wind drivers, there is bias magnetosphere's propose that underlying statistical effect (related more well-known...
We analyze the properties of relativistic (>700 keV) electron precipitation (REP) events measured by low-Earth-orbit (LEO) POES/MetOp constellation spacecraft from 2012 through 2023. Leveraging different profiles REP observed at LEO, we associate each event with its possible driver: waves or field line curvature scattering (FLCS). While typically precipitate electrons in a localized radial region within outer radiation belt, FLCS drives energy-dependent edge belt. Wave-driven is...
<p>The polar cap potential, a measure of the magnetosphere's response to solar wind, levels off during high wind electric field values. Several explanations have been proposed for this saturation effect, but there has no consensus. We show that may <em>merely be </em><em>perception</em> created by uncertainty in measurements and its propagation cap. Correcting reveals true is linear across full range These findings...