A5075476407- Lightning and Electromagnetic Phenomena
- Fire effects on ecosystems
- Electrical Fault Detection and Protection
- Ionosphere and magnetosphere dynamics
- High voltage insulation and dielectric phenomena
- Electrostatic Discharge in Electronics
- Earthquake Detection and Analysis
- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Electromagnetic Compatibility and Noise Suppression
- Fire Detection and Safety Systems
- Particle Detector Development and Performance
- Plant responses to water stress
- Atmospheric aerosols and clouds
- Solar and Space Plasma Dynamics
- Quantum Chromodynamics and Particle Interactions
- Combustion and Detonation Processes
- Advanced Optical Sensing Technologies
- Advanced Decision-Making Techniques
- Ocular and Laser Science Research
- Risk and Safety Analysis
- Geophysics and Sensor Technology
- Power Line Communications and Noise
- Radiation Detection and Scintillator Technologies
- Power Transformer Diagnostics and Insulation
Los Alamos National Laboratory
2010-2025
Florida Institute of Technology
2014-2025
High Energy Accelerator Research Organization
2023
Centre National de la Recherche Scientifique
2023
Technische Universität Dresden
2023
Aix-Marseille Université
2023
Vaisala (United States)
2011-2016
Numerical Algorithms Group (United Kingdom)
2015
University of Florida
2007-2014
Abstract Ground‐based and satellite‐based lightning locating systems are the most common ways to detect geolocate lightning. Depending upon frequency range of operation, LLSs may report a variety processes characteristics associated with flashes including channel formation, leader pulses, cloud‐to‐ground return strokes, M‐components, ICC cloud location, duration, peak current, radiated power energy, full spatial extent channels. Lightning data from different types often provide complementary...
It is generally thought that the lower positive charge region serves to enhance electric field at bottom of main negative and thereby facilitate launching a negatively‐charged leader toward ground. On other hand, presence excessive may prevent occurrence cloud‐to‐ground discharges by “blocking” progression descending from reaching ground thus “converting” potential flash an intracloud (or cloud‐to‐air) one. Assuming preliminary breakdown pulse train manifestation interaction...
We examine the various conceptual cloud charge configurations and scenarios leading to production of positive lightning with a view toward an explanation its observed properties. Data for 52 cloud‐to‐ground flashes containing 63 strokes recorded in Gainesville, Florida, 2007–2008 are presented discussed. The U.S. National Lightning Detection Network (NLDN) located 51 (96%) at distances 7.8 157 km from field‐measuring station. In 42 (81%) flashes, first (or only) leader‐return stroke sequence...
Abstract We report on a terrestrial gamma ray flash (TGF) that occurred 15 August 2014 coincident with an altitude‐triggered lightning at the International Center for Lightning Research and Testing (ICLRT) in North Central Florida. The TGF was observed by ground‐level network of ray, close electric field, distant magnetic Mapping Array (LMA), optical, radar measurements. Simultaneous LMA data indicate upward positive leader triggered induced relativistic runaway electron avalanches when tip...
We examined wideband electric fields, and magnetic field derivatives, narrowband VHF (36 MHz) radiation bursts produced by 157 compact intracloud discharges (CIDs). These poorly understood lightning events appear to be the strongest natural producers of HF‐VHF radiation. All transported negative charge upward (or lowered positive charge), 150 were located U.S. National Lightning Detection Network (NLDN), 149 them correctly identified as cloud discharges. NLDN‐reported distances from...
In this study, we identify and examine electric field pulse trains that are characteristic of preliminary breakdown in negative cloud‐to‐ground discharges but not followed by return stroke waveforms. We assume such manifestations the initiation downward stepped leaders fail to propagate all way ground refer these events as “attempted first leaders,” although some them were full‐fledged cloud discharges. examined a total 2475 records lightning acquired Gainesville, Florida, 2006, waveforms 33...
[1] We evaluated performance characteristics of the U.S. National Lightning Detection Network (NLDN) using rocket-triggered lightning data acquired in 2004-2009 at Camp Blanding, Florida. A total 37 negative flashes that contained leader/return stroke sequences (a 139) were triggered during these years. For all return strokes, locations channel terminations on ground known exactly, and for 122 them currents measured directly noninductive shunts. The NLDN recorded 105 Blanding strokes 34...
Abstract We present a detailed evaluation of performance characteristics the U.S. National Lightning Detection Network (NLDN) using, as ground truth, Florida rocket‐triggered lightning data acquired in 2004–2012. The overall set includes 78 flashes containing both initial stage and leader/return‐stroke sequences 2 composed only. In these 80 flashes, there are total 326 return strokes (directly measured channel‐base currents available for 290 them) 173 kiloampere‐scale (≥1 kA) superimposed...
On the basis of experimental evidence multiple reflections and modeling, we infer that, from electromagnetic point view, so‐called compact intracloud lightning discharge (CID) is essentially a bouncing‐wave phenomenon. The shortest radiating‐channel length appears to be about 100 m. Reflections, occurring at CID channel ends, influence magnitude overall electric field waveform are responsible for its fine structure, as well as, by inference, “noisiness” dE/dt waveforms accompanying HF‐VHF...
Abstract The U.S. National Lightning Detection Network (NLDN) detection efficiency (DE) and classification accuracy (CA) for cloud discharge (IC) activity (identified here by a sequence of non‐return‐stroke‐type electric field pulses not accompanied channels to ground) were evaluated using optical data acquired at the LOG (Lightning Observatory in Gainesville), Florida. Our ground truth “IC events” include 26 “isolated IC (complete flashes), 58 events before first return stroke,” 69 after...
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...
In this study, we examine the characteristics of electric field pulse trains that are attributed to preliminary breakdown in negative cloud-to-ground lightning discharges and compare them those similar associated with attempted leaders. The data were acquired 2006 Gainesville, Florida. largest pulses train can exceed magnitude following first return-stroke pulse. arithmetic mean duration interpulse interval for 4.8 65 mus, respectively. leaders 17 73 This implies ground contain a larger...
Abstract We examine downward leader characteristics for negative first return strokes, along with estimated stroke peak currents, lightning occurring over land and ocean reported by the U.S. National Lightning Detection Network (NLDN). For time, to best of our knowledge, we report independent evidence that supports observations locating systems higher currents than land. analyzed in five circular regions, each 50 km diameter. In western Florida, median stepped‐leader duration was 17% shorter...
We estimated electrical parameters of 48 located compact intracloud discharges (CIDs) using their measured electric fields and vertical Hertzian dipole approximation. This approximation is consistent with the more general bouncing‐wave CID model for a reasonably large subset allowed combinations propagation speed channel length. For nine events, we lengths from observed reflection signatures in dE/dt waveforms assumed speeds between 2 × 10 8 m/s 3 m/s, which limit range values. 2.5 (average...
Abstract We estimated the performance characteristics of Global Lightning Dataset (GLD360) using rocket‐and‐wire triggered lightning data acquired at Camp Blanding, Florida, in 2011–2013. The set consisted 201 return strokes and 84 kiloampere‐scale (≥1 kA) superimposed pulses (initial continuous current M components) 43 flashes. All events transported negative charge to ground. GLD360 detected 75 4 29 resultant detection efficiencies were 67% for flashes, 37% strokes, 4.8% pulses. Out one...
Abstract The Radio Frequency Sensor (RFS), a new radio frequency lightning detector, was launched into geosynchronous orbit in December 2021, and first collected data January 2022. RFS is specialized software‐defined receiver that detects, records, reports impulsive broadband radio‐frequency (RF) signatures from the very high (VHF; 30–300 MHz) range. Its vantage point Western hemisphere provides unique opportunities to study evolution of RF over durations thunderstorms Americas Pacific...
Abstract Each stroke in a negative cloud‐to‐ground lightning flash is composed of downward leader and upward return processes, which are usually modeled individually. The first stepped starts with preliminary breakdown (PB) often viewed as separate process. We present the unified engineering model for computing electric field produced by sequence PB, leader, serving to transport charge ground. assume that negatively charged channel extends fashion during both PB stages. step involves current...
We examine relative magnitudes of electric field peaks first and subsequent return strokes in negative cloud‐to‐ground lightning flashes recorded Florida, Austria, Brazil, Sweden. On average, the peak stroke is appreciably, 1.7 to 2.4 times, larger than (except for studies Austria where ratio varies from 1.0 2.3, depending on methodology instrumentation). Similar results were previously reported Sweden, Sri Lanka. For comparison, directly measured currents are, a factor 2.3 2.5 those...
Abstract In this study, we analyze 44 terrestrial gamma‐ray flashes (TGFs) detected by the Fermi Gamma‐ray Burst Monitor (GBM) occurring in 2014–2016 conjunction with data from U.S. National Lightning Detection Network (NLDN). We examine characteristics of magnetic field waveforms measured NLDN sensors for 61 pulses that occurred within 5 ms start‐time TGF photon flux. For 21 (out 44) TGFs, associated pulse almost simultaneously (that is, 200 μs of) TGF. One had two μs. The median absolute...