A5040184335- Lightning and Electromagnetic Phenomena
- Earthquake Detection and Analysis
- Ionosphere and magnetosphere dynamics
- Fire effects on ecosystems
- Electrical Fault Detection and Protection
- Electrostatic Discharge in Electronics
- Power Line Communications and Noise
- High voltage insulation and dielectric phenomena
- Radiation Detection and Scintillator Technologies
- Astrophysics and Cosmic Phenomena
- Seismic Waves and Analysis
- Radioactivity and Radon Measurements
- Electromagnetic Compatibility and Noise Suppression
- Nuclear Physics and Applications
- Plant responses to water stress
- Magneto-Optical Properties and Applications
- Radioactive contamination and transfer
- Nuclear and radioactivity studies
- Advanced Optical Sensing Technologies
- Meteorological Phenomena and Simulations
- Parallel Computing and Optimization Techniques
- Computational Physics and Python Applications
- Particle Detector Development and Performance
- Real-time simulation and control systems
- Planetary Science and Exploration
Los Alamos National Laboratory
1999-2024
University of California, Santa Cruz
2023
New Mexico Institute of Mining and Technology
2001-2021
University of Oklahoma
1996
With the use of a NaI scintillation detector, bursts radiation with energies in excess 1 MeV were recorded at mountain‐top observatory immediately before three, nearby cloud‐to‐ground, negative lightning strikes. Coincident recordings electric field changes due to discharges showed that, each case, began between and 2 milliseconds continued until onset first return stroke. This was associated approaching stepped‐leaders may have influenced their development.
The field program of the Thunderstorm Electrification and Lightning Experiment (TELEX) took place in central Oklahoma, May–June 2003 2004. It aimed to improve understanding interrelationships among microphysics, kinematics, electrification, lightning a broad spectrum storms, particularly squall lines storms whose electrical structure is inverted from usual vertical polarity. was built around two permanent facilities: KOUN polarimetric radar Oklahoma Mapping Array. In addition, balloon-borne...
With an X ray detector designed for flight on a free balloon, we obtained sounding of intensity and electric‐field strength in mesoscale convective system (MCS) near Norman, Oklahoma, the spring 1995. The balloon passed through region high electric field strength, at which time increase about 2 orders magnitude occurred, lasting approximately 1 min. returned to background levels lightning flash that reduced measured balloon. This observation suggests production mechanism rays observed is...
Since 1998 the Los Alamos Sferic Array (LASA) has recorded electric field change signals from lightning in support of radio frequency (RF) and optical observations by Fast On‐orbit Recording Transient Events (FORTE) satellite. By “sferic” (a colloquial abbreviation for “atmospheric”), we refer to a remote measurement transient produced flash. LASA consisted five stations New Mexico was expanded 11 Mexico, Texas, Florida, Nebraska 1999. During 2 years operation described this paper, acquired...
On 3 August 2010 an extensive lightning flash was triggered over Langmuir Laboratory in New Mexico. The upward positive leader propagated into the storm's midlevel negative charge region, extending a horizontal area of 13 × km and 7.5 altitude. storm had normal‐polarity tripolar structure with upper charge. Lightning Mapping Array (LMA) observations were used to estimate velocities along various branches, which range 1–3 10 4 m s −1 , slower than other studies. initiated at 3.4 altitude, but...
Abstract Sample return capsules (SRCs) entering Earth’s atmosphere at hypervelocity from interplanetary space are a valuable resource for studying meteor phenomena. The 2023 September 24 arrival of the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer SRC provided an unprecedented chance geophysical observations well-characterized source with known parameters, including timing trajectory. A collaborative effort involving researchers 16 institutions...
During a balloon flight into and above the stratiform region of mesoscale convective system, we observed three x‐ray pulses while was at an altitude approximately 15 km MSL (atmospheric pressure 130 mb). These were one to two orders magnitude background count rate with peak fluxes between 37 270 (cm²‐s‐sr) −1 durations about second. No significant electric field measured time these pulses.
Narrow bipolar events (NBE) are the electromagnetic signature of a distinct class impulsive and energetic intra‐cloud discharge that occurs in some thunderstorms. NBE characterized by strong VHF RF emissions waveforms when observed broadband field‐change antennas at large distances. These discharges may occur isolation or precede perhaps initiate conventional flashes. When close range, exhibit electrostatic field changes addition to radiation change. At extremely induction fields dominate...
[1] An intracloud lightning flash in central New Mexico began with the initiation of a negative stepped leader at an altitude 8.2 km above sea level. As this propagated eastward and upward, 9.1 level it passed about 200 m to north balloon-borne, electric field-change instrument (Esonde). After first stopped, second near point origin leader, but away from Esonde. From changes vectors locations impulsive radio frequency sources detected by lightning-mapping array (LMA), we conclude following:...
A color photograph has been obtained of a negative lightning leader in clear air at 10.3 km altitude. The individual steps are resolved as relatively straight segments least ~200 m length, between sharp kinks (nodes) the channel. Each node is accompanied by group streamers ~100 length. One an unconnected secondary with both ends. Lightning Mapping Array observations show that was part intracloud (IC) flash. observation shows leaders near 10 altitude order magnitude longer than values...
Abstract The dissonant development of positive and negative lightning leaders is a central question in atmospheric electricity. It also the likely root cause other reported asymmetries between flashes, including ones regarding: stroke multiplicity, recoil activity, leader velocities, emission energetic radiation. In an effort to contrast different polarities, we highlight staggering differences two rocket‐triggered flashes. flash beginning with upward exhibits initial continuous current...
Balloon‐borne gamma‐ray and electric‐field‐change instruments were launched into a daytime summer thunderstorm to evaluate new experimental design test hypotheses for the production of transient luminous events (TLE) (eg. sprites, blue jets) in mesosphere. While ascending, instrument triggered many times on signals from instrument, recording background at those times. A greater than three‐fold increase flux was observed as balloon descended through anvil where strong electric field suspected...
A set of 133 positive narrow bipolar lightning events located by the Los Alamos Sferic Array (LASA) is examined. The were selected because their fast electric field change (EFC) records show a secondary peak, following primary which consistent with what would be expected for propagating current pulse reflecting off an impedance discontinuity along transmission line. With assumed propagation speed, time difference between and (reflected) peak in record offers direct technique estimating...
A triggered lightning flash that transferred negative charge to ground in central New Mexico produced more than three levels of branching above the main channel a 1 km vertical field view. high‐speed video recording shows had about 50 brief luminous pulses, many which were superimposed on slowly changing persistent luminosity. In contrast, superposition was rare uppermost visible branches because pulses first appeared preexisting dark channels before merging into channel. This observation...
Abstract In 1995, a series of four balloon flights with an X‐ray spectrometer and electric field meter were conducted to examine if strong fields could accelerate, perhaps multiply, cosmic ray secondary electrons produce bremsstrahlung X‐rays. intensities between 10 1000 times that normal background observed in conjunction fields. Both negative positive polarity (as referenced the vertical field) produced X‐rays, which lasted for time scales on order tens seconds. It was also increased...
Abstract During the 2022 New Mexico monsoon season, we deployed two X‐ray scintillation detectors, coupled with a 180 MHz data acquisition system to detect X‐rays from natural lightning at Langmuir Lab mountain‐top facility, located 3.3 km above mean sea level. Data was triggered by an electric field antenna calibrated pick up within few of detectors. We report energies over 240 individual photons, ranging between 13 keV and 3.8 MeV, as registered LaBr 3 (Ce) detector. These detections were...
A new balloon-borne instrument designed by the author detects x rays produced in thunderstorms. The uses a sodium iodide (NaI) scintillation detector, and flies on small meteorological balloon. three bin (30 to 60, 60 90, 90 120 keV) x-ray spectrum is acquired every 0.25 s. deployment of these detectors with electric-field meters has resulted several vertical profiles intensity strength. These data support hypothesis that electric field generated thunderstorm can produce energetic electrons,...
Models for outdoor radon progeny near the Earth's surface provide improved predictions of disequilibrium if two effective particle size groups are used and diffusion through a thin laminar sub-layer just above is included. Calculations with new computer code, RPOUT, compared data. An unanticipated finding prediction situations where activity concentration can exceed that its parent nuclide. This provides theoretical support previously reported controversial observations.
Abstract When the electric field below a thunderstorm or other electrified cloud is around 10 kV/m, it sometimes possible to initiate (“trigger”) an upward‐propagating lightning‐leader by launching rocket that uncoils wire from ground. The triggered leader propagates upward tip of lifted rocket. channel hot enough, flash visible. Triggering common when carries positive charge, but not negative charge. This article about four flashes consisting leaders branched into low‐altitude regions...
During the Summer and Fall of 1998 we launched five balloon‐borne instruments into thunderstorms to observe changes in vertical component electric field caused by lightning. Four these were for measurement change only. The fifth was part a larger package that included gamma radiation detector GPS receiver on board. We have processed electric‐field‐change data from two flights. discuss examples observed at altitude compare them with National Lightning Detection Network (NLDN) cloud‐to‐ground...
[1] We present analysis of thunderstorm data collected with a liquid nitrogen–cooled germanium spectrometer energies between 13 keV–2.6 MeV that was deployed at Langmuir Lab on South Baldy Peak in New Mexico for June through August 2005. The motivation to search gamma ray emissions from radioactive chlorine-39 and chlorine-38, as suggested by Greenfield et al. (2003). Based the observations, we place an upper limit rate chlorine production such process (6.8 × 10−17 atoms per argon atom)....