A5053583356- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Magnetic confinement fusion research
- Particle accelerators and beam dynamics
- Earthquake Detection and Analysis
- Lightning and Electromagnetic Phenomena
- Astro and Planetary Science
- Gyrotron and Vacuum Electronics Research
- Geomagnetism and Paleomagnetism Studies
- Plasma Diagnostics and Applications
- Atmospheric Ozone and Climate
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Laser-induced spectroscopy and plasma
- Fusion materials and technologies
- Astrophysics and Cosmic Phenomena
- Nuclear Physics and Applications
- Geophysics and Gravity Measurements
- Atmospheric aerosols and clouds
- Meteorological Phenomena and Simulations
- Laser-Plasma Interactions and Diagnostics
- Solar Radiation and Photovoltaics
- GNSS positioning and interference
- Dust and Plasma Wave Phenomena
- Seismic Waves and Analysis
University of Washington
2013-2024
Earth and Space Research
2012-2023
University of Guelph
2021
Seattle University
2001-2020
Texas A&M University
2019
Hudson Institute
2019
John Wiley & Sons (United States)
2019
Oak Ridge National Laboratory
2006-2015
CEA Cadarache
2013
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2013
Abstract. On board the four Cluster spacecraft, Ion Spectrometry (CIS) experiment measures full, three-dimensional ion distribution of major magnetospheric ions (H+, He+, He++, and O+) from thermal energies to about 40 keV/e. The consists two different instruments: a COmposition DIstribution Function analyser (CIS1/CODIF), giving mass per charge composition with medium (22.5°) angular resolution, Hot Analyser (CIS2/HIA), which does not offer resolution but has better (5.6°) that is adequate...
Lightning may be initiated via an electron avalanche that occur when energetic electrons (∼1 MeV) are accelerated by thunderstorm electric fields to velocities sufficient produce new during ionizing collisions with nitrogen or oxygen molecules. For the occur, field must exceed a critical value called breakeven field. At any altitude is substantially less than usually thought necessary either for dielectric breakdown streamer propagation. We show 23 soundings through thunderstorms seem...
A control and an x‐ray detector were flown into thunderstorms in 1984. The found statistically significant radiation flux increases the energy range 5 to > 110 keV for time intervals of several seconds each. Simultaneously showed no changes. is sometimes seen increase prior observed lightning discharges then return background levels within 0.1 a flash initiation. temporal development these bursts discussed related inferring scale size emitting regions.
We present Wind spacecraft observations of solar impulsive electron events associated with locally generated Langmuir waves during type III radio bursts. The electrons had energies from ~600 eV to greater than 300 keV. Local emissions these fluxes generally coincided the arrival 2-12 keV electrons. A survey 27 over 1 yr shows that there were few occurrences distributions (~96 s averaged) unstable and none a substantial growth rate (>3 × 10-2 s-1) or endured for more 96 s. Intense occurred on...
Five solar impulsive ∼1–10² keV electron events were detected while the WIND spacecraft was inside magnetic cloud observed upstream of Earth on October 18–20, 1995. The type III radio bursts produced by these electrons can be directly traced from ∼1 AU back to X‐ray flares in active region AR 7912, implying that at least one leg magnetically connected region. Analysis arrival times shows lengths field lines vary ∼3 near exterior ∼1.2 center, consistent with a model force‐free helical flux...
Pseudomonas aeruginosa is a leading cause of hospital-associated infections in the seriously ill, and primary agent chronic lung cystic fibrosis patients. A major obstacle to effective control P. its intrinsic resistance most antibiotic classes, which results from chromosomally encoded drug-efflux systems multiple acquired mechanisms selected by years aggressive therapy. These factors demand new strategies drugs prevent treat infections. Herein, we describe monoclonal antibody (mAb)...
Particle and field data obtained by eight ISEE spacecraft experiments are used to define more precisely the characteristics of high‐latitude boundary region plasma sheet. We find that there is a immediately adjacent sheet whose particle distinctly different from its neighbors, lobe This supports intense ion flows, field‐aligned currents, large amplitude electric fields, enhanced broad band electrostatic noise. A detailed analysis events detected on April 19, 1978, shows distributions in...
Abstract We use World Wide Lightning Location Network (WWLLN) data on the radiated radio frequency electromagnetic energy per stroke to identify upper tip of global lightning distribution. The mean is about 1,000 J in very low band between 5 and 18 kHz, while distribution used this paper limited strokes that above 1 MJ, 3 orders magnitude mean. It shown these energies are representative optical distribution, first identified by Turman (1977) 10 GW stroke, which he termed “superbolts.” peaks...
Abstract World Wide Lightning Location Network (WWLLN) data on global lightning are used to investigate the increase of total strokes at Arctic latitudes. We use summertime from June, July, and August (JJA) which average >200,000 each year above 65°N for years 2010–2020. minimize possible influence WWLLN network detection efficiency increases by normalizing our results during northern summer year. The ratio occurring a given latitude, compared strokes, with time, indicating that is...
The high‐resolution germanium detector aboard the MAXIS (MeV Auroral X‐ray Imaging and Spectroscopy) balloon payload detected nine bursts with significant flux extending above 0.5 MeV during an 18 day flight over Antarctica. These minutes‐to‐hours‐long events are characterized by extremely flat spectrum (∼E −2 ) similar to first event discovered in 1996, indicating that bulk of parent precipitating electrons is at relativistic energies. were between magnetic latitudes 58°–68° (L‐values...
BARREL is a multiple-balloon investigation designed to study electron losses from Earth's Radiation Belts. Selected as NASA Living with Star Mission of Opportunity, augments the Belt Storm Probes mission by providing measurements relativistic precipitation pair Antarctic balloon campaigns that will be conducted during Austral summers (January-February) 2013 and 2014. During each campaign, total 20 small (∼20 kg) stratospheric balloons successively launched maintain an array ∼5 payloads...
Abstract The Balloon Array for Radiation belt Relativistic Electron Losses (BARREL) studies the loss of energetic electrons from Earth's radiation belts. BARREL's array slowly drifting balloon payloads was designed to capitalize on magnetic conjunctions with NASA's Van Allen Probes. Two campaigns were conducted Antarctica in 2013 and 2014. During first campaign January February 2013, there three moderate geomagnetic storms SYM‐H min < −40 nT. Similarly, two minor occurred during second...
On August 20, 1996, balloon‐borne X‐ray detectors observed an intense event as part of a French balloon campaign near Kiruna, Sweden, at 1532 UT (1835 magnetic local time), on L shell 5.8. The energy spectrum this shows the presence X rays with energies > 1 MeV, which are best accounted for by atmospheric bremsstrahlung from monoenergetic ∼1.7 MeV precipitating electrons. Ultraviolet images Polar satellite and energetic particle data Los Alamos geosynchronous satellites show onset small...
After many years of fusion research, the conditions needed for a D–T reactor have been approached on Tokamak Fusion Test Reactor (TFTR) [Fusion Technol. 21, 1324 (1992)]. For first time unique phenomena present in plasma are now being studied laboratory plasma. The magnetic experiments to study plasmas using nearly equal concentrations deuterium and tritium carried out TFTR. At maximum power 10.7 MW, 39.5 MW neutral-beam heating, supershot discharge 6.7 high-βp following current rampdown....
Using CLUSTER/CODIF data from close to ∼19 Re in the magnetotail, we have performed a superposed epoch analysis of storm time and nonstorm substorms determine how ion composition changes during substorm. We find that median O + density pressure plasma sheet are factor 5 higher times than times. However, do not observe significant substorm would indicate ionospheric outflow is playing dynamic role loading or triggering at this location. There differences between substorms, it intriguing...
We present the first quantitative comparison of precipitating and geomagnetically trapped electron flux during a relativistic depletion event. Intense bremsstrahlung X‐ray emission from precipitation was observed on January 19–20, 2000 (21:20–00:45 UT) by germanium spectrometer MAXIS balloon payload (−7.2 to −9.3 E, 74 S corresponding IGRF L = 4.7, 1920–2240 MLT). A rapid decrease in geosynchronous >2 MeV simultaneously at GOES‐8 GOES‐10, between 0.34–3.6 GPS ns33 4.7. The observations...
We have studied in detail a Wind spacecraft crossing of the low‐latitude dusk flank magnetosheath, magnetopause (MP), and boundary layer (LLBL) when local magnetic shear across MP was low (<30°) interplanetary field (IMF) northward. find that magnetosheath flow tangential to slows down initially as one moves from bow shock toward MP. However, close this speeds up is approached. The source acceleration likely be force associated with draping lines around Magnetic flux pile‐up plasma...
We present the first observation of a solar impulsive electron event spanning entire wind‐suprathermal particle energy range (few eV to hundreds keV), obtained with 3‐D Plasma and Energetic Particle experiment on WIND spacecraft. The spectrum fits power‐law ∼ E −3 from ∼40 keV down peak at ≲ 1 keV, significant flux detected ∼0.5 keV. Since such low electrons in ionized hydrogen is much less than column density corona, they must be accelerated high, ∼1 R ⊙ (solar radius) above photosphere,...