A5069707097- Solar and Space Plasma Dynamics
- Gamma-ray bursts and supernovae
- Ionosphere and magnetosphere dynamics
- Lightning and Electromagnetic Phenomena
- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Astro and Planetary Science
- Pulsars and Gravitational Waves Research
- Earthquake Detection and Analysis
- Particle Detector Development and Performance
- Stellar, planetary, and galactic studies
- Nuclear Physics and Applications
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Social Policy and Reform Studies
- Housing, Finance, and Neoliberalism
- Romani and Gypsy Studies
- Solar Radiation and Photovoltaics
- Dark Matter and Cosmic Phenomena
- Mechanics and Biomechanics Studies
- Urbanization and City Planning
- Radiation Detection and Scintillator Technologies
- High voltage insulation and dielectric phenomena
- Fire effects on ecosystems
- Rural development and sustainability
University of California, Santa Cruz
2015-2024
University of California System
2007-2024
University of California, San Diego
2020-2024
Earth Networks (United States)
2023
New Mexico Institute of Mining and Technology
2023
The Recovery Center
2022
South Tyneside and Sunderland NHS Foundation Trust
2022
Sunderland Royal Hospital
2022
Pepperdine University
1997-2021
Marymount University
2016
The Nuclear Spectroscopic Telescope Array (NuSTAR) mission, launched on 2012 June 13, is the first focusing high-energy X-ray telescope in orbit. NuSTAR operates band from 3 to 79 keV, extending sensitivity of far beyond ∼10 keV cutoff achieved by all previous satellites. inherently low background associated with concentrating light enables probe hard sky a more than 100-fold improvement over collimated or coded mask instruments that have operated this bandpass. Using its unprecedented...
We summarize Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) hard X-ray (HXR) and γ-ray imaging spectroscopy observations of the intense (X4.8) line flare 2002 July 23. In initial rise, a new type coronal HXR source dominates that has steep double-power-law spectrum no evidence thermal emission above 10 keV, indicating substantial electron acceleration to tens keV early in flare. subsequent impulsive phase, three footpoint sources with much flatter spectra appear, together...
Terrestrial gamma-ray flashes (TGFs) from Earth's upper atmosphere have been detected with the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) satellite. The spectra typically extend up to 10 20 megaelectron volts (MeV); a simple bremsstrahlung model suggests that most of electrons produce gamma rays energies on order 40 MeV. RHESSI detects TGFs per month, corresponding ∼50 day globally, perhaps many more if they are beamed. Both frequency occurrence and maximum photon energy...
It is now well established that both thunderclouds and lightning routinely emit x-rays gamma-rays. These emissions appear over wide timescales, ranging from sub-microsecond bursts of associated with leaders, to sub-millisecond gamma-rays seen in space called terrestrial gamma-ray flashes, minute long glows on the ground or near cloud by aircraft balloons. In particular, flashes (TGFs), which are thought be emitted thunderclouds, so bright they sometimes saturate detectors spacecraft hundreds...
The Gamma‐ray Burst Monitor (GBM) on the Fermi Space Telescope detected 12 intense terrestrial gamma ray flashes (TGFs) during its first year of observation. Typical maximum energies for most TGFs are ∼30 MeV, with one TGF having a 38 MeV photon; two softer and longer than others. After correcting instrumental effects, representative bright is found to have fluence ∼0.7 photons cm −2 . Pulses either symmetrical or faster risetimes fall times; they well fit Gaussian lognormal functions....
Monte Carlo simulations of the runaway breakdown air are used to calculate spectra terrestrial gamma‐ray flashes (TGFs), which then compared with RHESSI and CGRO/BATSE observations. It is found that recent spectrum not consistent a source altitude above 24 km but can be well fit by in range 15–21 km, depending upon electric field geometry source. Because 15 unusual for tops thunderstorms, especially at low latitudes, lower than typical minimum sprite altitudes, data imply thunderstorms...
We study X-ray and variability distance of GX 339-4. derive d>7 kpc, based on recent determination the binary parameters. data from Ginga/ASM, CGRO/BATSE, RXTE/ASM, PCA HEXTE. From 1987 to 2004, 339-4 underwent 15 outbursts went through all known states black-hole binaries. also present initial stage 2004 outburst. then colour-colour colour-flux correlations. In hard state, there is a strong anticorrelation between 1.5-5 3-12 keV spectral slopes, which we explain by thermal Comptonization...
We report observations and analysis of 30 kHz radio emissions (sferics) from lightning discharges associated with 26 terrestrial gamma ray flashes (TGFs) recorded by the RHESSI satellite over Caribbean Americas, between 1500 4000 km away magnetic field sensors located at Duke University. Thirteen TGFs are found to occur within −3/+1 ms positive polarity direction subsatellite point, strongly indicating that linked these discharges. The event timing sferic finding reveals a ∼300 radius circle...
Atmospheric electric field change (sferic) waveforms were detected at Los Alamos Sferic Array stations in association with terrestrial gamma‐ray flashes (TGFs). Five TGF sferic sufficiently close range all found to be consistent a positive‐polarity intracloud (+IC) discharge process which transported electrons upward. The amplitudes of the events among top 5% IC flashes. Altitudes obtained from ionosphere reflections for two closer 13.6 km and 11.5 km. These altitudes are lower than expected...
[1] Terrestrial Gamma-ray Flashes (TGFs) are brief pulses of energetic radiation observed in low-earth orbit. They associated with thunderstorms and lightning have been both as gamma-ray electron flashes depending on the position spacecraft respect to source. While TGFs detected short lasting less than 1 ms, most seen by Fermi Burst Monitor (GBM) durations greater ms are, instead, result electrons traveling from sources along geomagnetic field lines. We perform spectral analysis three...
We report the observation with North Alabama Lightning Mapping Array (LMA) related to a terrestrial gamma‐ray flash (TGF) detected by RHESSI on 26 July 2008. The LMA data explicitly show TGF was produced during initial development of compact intracloud (IC) lightning between negative charge region centered at about 8.5 km above sea level (−22°C temperature level) higher positive 13 km, both confined convective core an isolated storm in close proximity footprint. After occurrence source high...
This paper presents detailed comparisons between terrestrial gamma‐ray flashes (TGFs) detected by the RHESSI satellite and lightning processes observed Los Alamos Sferic Array (LASA). It was found that all RHESSI‐detected TGFs were related to normal intracloud transported electrons upward in cloud. Detailed temporal suggest are more likely small, rather than large, pulses, mostly at level of 10 −1 −10 0 V/m when pulses normalized an observation distance 100 km. The corresponding peak current...
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...