A5102839107- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Astro and Planetary Science
- Spacecraft Design and Technology
- Geomagnetism and Paleomagnetism Studies
- Atmospheric Ozone and Climate
- Earthquake Detection and Analysis
- Plasma Diagnostics and Applications
- Planetary Science and Exploration
- Geophysics and Gravity Measurements
- Satellite Communication Systems
- Atmospheric and Environmental Gas Dynamics
- Geology and Paleoclimatology Research
- Drilling and Well Engineering
- Oceanographic and Atmospheric Processes
- Copper Interconnects and Reliability
- Geological Modeling and Analysis
- Aerospace Engineering and Energy Systems
- Inertial Sensor and Navigation
- Semiconductor materials and devices
- GNSS positioning and interference
- Seismic Waves and Analysis
- Molecular Junctions and Nanostructures
- Geological and Geophysical Studies
- Spectroscopy and Laser Applications
Goddard Space Flight Center
2012-2022
National Aeronautics and Space Administration
2022
University College Cork
2015-2016
University of New Hampshire
2006-2011
University of New Hampshire at Manchester
2008
Dartmouth College
2004-2005
Montana State University
2004
Queen Mary University of London
2000
Abstract In this study, by simulating the wave‐particle interactions, we show that subrelativistic/relativistic electron microbursts form high‐energy tail of pulsating aurora (PsA). Whistler‐mode chorus waves propagate along magnetic field lines at high latitudes cause precipitation bursts electrons with a wide energy range from few kiloelectron volts (PsA) to several megaelectron (relativistic microbursts). The rising tone elements individual and internal modulation PsA frequency hertz. for...
[1] Pulsating aurora is a common phenomenon generally believed to occur mainly in the aftermath of substorm, where dim long-period pulsating patches appear. The study determines temporal and spatial evolution events using two THEMIS all-sky imager stations, at Gillam (66.18 magnetic latitude, 332.78 longitude, midnight 0634 UT) Fort Smith, (67.38 306.64 0806 along roughly same invariant latitude. Parameters have been calculated from database 74 119 days good optical data within period...
Observations of a pulsating aurora event occurring on 11 February 2008, using the Time History Events and Macroscale Interactions during Substorms (THEMIS) All‐Sky Imager (ASI) array, indicate spatially temporally continuous with duration greater than 15 h covering region maximum size 10 magnetic local time. The optical pulsations are at times locally interrupted or drowned out by auroral substorm activity but observed in same location once discrete recedes. following breakup appear to be...
In this work we relate the magnetic and topological parameters of twelve interplanetary clouds to associated solar active regions. We use a cylindrically symmetric constant‐α force‐free model derive field line twist, total current, flux from in situ observations clouds. compare these properties with those regions, which infer vector magnetograms. Our comparison fluxes currents reveals: (1) ratios Φ MC /Φ AR tend be order unity, (2) current I / are orders magnitude smaller, (3) there is...
Density functional theory and density tight-binding are applied to model electron transport in copper nanowires of approximately 1 nm 3 diameters with varying crystal orientation surface termination. The studied found be metallic irrespective diameter, and/or Electron transmission is highly dependent on Nanowires oriented along the [110] crystallographic axis consistently exhibit highest while oxidized show significantly reduced compared unterminated nanowires. Transmission per unit area...
The occurrence of Pi1B pulsations is well‐documented, including the fact that these can be observed both on ground and at geosynchronous orbit substorm onset, although information about their propagation characteristics has been lacking. In this paper, data are presented from FAST, GOES 9 various stations show simultaneous observations in association with an onset. While compressional nature, FAST presence shear mode waves, implying conversion some type must take place region between...
The ACES‐High rocket, part of the Auroral Current and Electrodynamics Structure (ACES) mission launched from Poker Flat Research Range on 29 January 2009, obtained first in situ measurements indicative both observational characteristics associated with ionospheric feedback instability as it flew through an auroral arc its return current region. observed Alfvénic wave structures localized areas roughly 10 km near boundaries region discrete increased electron density a temperature...
Pulsating aurora are common diffuse-like aurora. Studies have suggested that they contain higher energy particles than other types and possibly linked to substorm activity. There has yet be a quantitative statistical study of the variation in pulsating content related substorms. We analyzed inverted from 53 events using Poker Flat Incoherent Scatter Radar. To reduce uncertainty, we split differential flux into low high limit 30 keV. also lower altitude boundary electron density profile,...
Abstract We present simultaneous observations of magnetosphere‐ionosphere‐thermosphere coupling over Svalbard during a traveling convection vortex (TCV) event. Various spaceborne and ground‐based instruments made coordinated measurements, including magnetometers, particle detectors, an all‐sky camera, European Incoherent Scatter (EISCAT) Radar, Super Dual Auroral Radar Network (SuperDARN), SCANning Doppler Imager (SCANDI). The recorded TCVs associated with sudden change in solar wind dynamic...
Electron transport is studied in surface oxidized single-crystal copper thin films with a thickness of up to 5.6 nm by applying density functional theory and tight binding methods determine electron properties within the ballistic regime. The variation transmission as function film well different contributions overall depth into examined. Transmission at surfaces found be universally low. Films greater than 2.7 exhibit similar behavior local per unit area from surface; initially increases...
We are developing a laser and electro-optic technology to remotely measure Sodium (Na) by adapting existing lidar with space flight heritage. The developed instrumentation will serve as the core for planning of an Heliophysics mission targeted study composition dynamics Earth's mesosphere based on spaceborne that mesospheric Na layer. present performance results from our diode-pumped tunable Q-switched self-Raman c-cut Nd:YVO4 intra-cavity frequency doubling produces multi-watt 589 nm...
The FASTSAT spacecraft, which was launched on November 19, 2010 the DoD STP-S26 mission, carries three instruments developed in joint collaboration by NASA GSFC and US Naval Academy: PISA, TTI, MINI-ME. <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1,2</sup> As part of a rapid-development, low-cost instrument design fabrication program, these were perfect match for FASTSAT, designed built less than one year. These instruments, while...
Earth and Space Science Open Archive This work has been accepted for publication in Geophysical Research Letters. Version of RecordESSOAr is a venue early communication or feedback before peer review. Data may be preliminary. Learn more about preprints. preprintOpen AccessYou are viewing the latest version by default [v1]Relativistic Electron Microbursts as High Energy Tail Pulsating Aurora...
Information on the detailed charge and energy spectra of galactic solar cosmic rays is required for a better understanding production, acceleration modulation those rays. This experiment consists set three detector assemblies to measure differential protons heavier nuclei through calcium (Z = 20) in range 400 Kev 1 Bev/nucleon, an extensive electronics system implement logic, perform pulse height analysis, particle fluxes, monitor performance interface with OGO data system. The systems...