A simulation study on the electric field spectral dependence of thunderstorm ground enhancements and gamma ray glows

Cramer, E. S.; Mailyan, B.; Célestin, Sébastien; Dwyer, J. R.

doi:10.1002/2016jd026422

Cited by 16 publications

(20 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This mechanism requires field strength of just a fraction of E t but gives the cosmic background electron and positron sufficient extra energy to produce enhanced fluxes of gamma rays. The spectral shape resulting from RREA and MOS was also investigated by Cramer et al () who found similar spectral behavior as reported by Chilingarian et al ().…”

Section: Introductionsupporting

confidence: 71%

Gamma Ray Glow Observations at 20‐km Altitude

et al. 2019

View full text Add to dashboard Cite

In the spring of 2017 an ER‐2 aircraft campaign was undertaken over continental United States to observe energetic radiation from thunderstorms and lightning. The payload consisted of a suite of instruments designed to detect optical signals, electric fields, and gamma rays from lightning. Starting from Georgia, USA, 16 flights were performed, for a total of about 70 flight hours at a cruise altitude of 20 km. Of these, 45 flight hours were over thunderstorm regions. An analysis of two gamma ray glow events that were observed over Colorado at 21:47 UT on 8 May 2017 is presented. We explore the charge structure of the cloud system, as well as possible mechanisms that can produce the gamma ray glows. The thundercloud system we passed during the gamma ray glow observation had strong convection in the core of the cloud system. Electric field measurements combined with radar and radio measurements suggest an inverted charge structure, with an upper negative charge layer and a lower positive charge layer. Based on modeling results, we were not able to unambiguously determine the production mechanism. Possible mechanisms are either an enhancement of cosmic background locally (above or below 20 km) by an electric field below the local threshold or an enhancement of the cosmic background inside the cloud but then with normal polarity and an electric field well above the Relativistic Runaway Electron Avalanche threshold.

show abstract

Section: Introductionsupporting

confidence: 71%

Gamma Ray Glow Observations at 20‐km Altitude

et al. 2019

View full text Add to dashboard Cite

show abstract

“…The technique could be made more sensitive to E ‖ by adding antennas that are sensitive to the 1 to 10 MHz band (see Trinh et al, ). For moderate‐to‐high E ‖ fields at low altitude above the ground, one would expect a clear increase in the count rate of particle detectors on the ground (see, e.g., Chilingarian et al, ; Cramer et al, ). We have searched for enhanced count rates in the LORA detectors (Wempe, ) but not found any, which is supporting the fact that the fields at low altitude are relatively weak.…”

Section: Cosmic‐ray Tomography Of Cloud Electric Fieldsmentioning

confidence: 99%

Determining Electric Fields in Thunderclouds With the Radiotelescope LOFAR

et al. 2020

View full text Add to dashboard Cite

An analysis is presented of electric fields in thunderclouds using a recently proposed method based on measuring radio emission from extensive air shower events during thunderstorm conditions. This method can be regarded as a tomography of thunderclouds using cosmic rays as probes. The data cover the period from December 2011 till August 2014. We have developed an improved fitting procedure to be able to analyze the data. Our measurements show evidence for the main negative-charge layer near the −10 • isotherm. This we have seen for a winter as well as for a summer cloud where multiple events pass through the same cloud and also the vertical component of the electric field could be reconstructed. On the day of measurement of some cosmic-ray events showing evidence for strong fields, no lightning activity was detected within 100 km distance. For the winter events, the top heights were between 5 and 6 km, while in the summer, typical top heights of 9 km were seen. Large horizontal components in excess of 70 kV/m of the electric fields are observed in the middle and top layers.

show abstract

“…This value is a standard for modeling RREA process in the large-scale atmospheric electric fields. However, Cramer et al (2017) showed that the accelerated electron spectrum significantly depends on the electric field strength near the RREA threshold, even for homogeneous electric fields. Until recently, there was an opinion that the spectrum of the accelerated electrons in fully developed RREAs should not depend on the electric field, and the electron spectrum can be described by an exponential function with a cutoff at 7.3 MeV (see, e.g., Dwyer & Babich, 2011).…”

Section: Spectral Dependencementioning

confidence: 99%

Analysis of Individual Terrestrial Gamma‐Ray Flashes With Lightning Leader Models and Fermi Gamma‐Ray Burst Monitor Data

Mailyan

Célestin

et al. 2019

JGR Space Physics

Self Cite

View full text Add to dashboard Cite

The Gamma‐ray Burst Monitor (GBM) onboard the Fermi spacecraft has observed many tens of sufficiently bright events, which are suitable for individual analysis. In our previous study, we fit individual, bright terrestrial gamma‐ray flashes (TGFs) with Relativistic Runaway Electron Avalanche (RREA) models for the first time. For relativistic‐feedback‐based models, the TGF‐producing electrons, which are seeded internally by a positive feedback effect, are usually accelerated in a large‐scale field with fully developed RREAs. Alternatively, lightning leader models may apply to either a large‐scale thunderstorm fields with fully developed RREAs or to inhomogeneous fields in front of lightning leaders where RREAs only develop partially. The predictions of the latter, inhomogeneous models for the TGF‐beaming geometry show some differences from estimations of the relativistic feedback models in homogeneous fields. In this work, we analyze a large sample of 66 bright Fermi GBM TGFs in the framework of lightning leader models, making comparisons with previous results from the homogeneous‐field RREA models. In most cases, the spectral analysis does not strongly favor one mechanism over the other, with 59% of the TGF events being best fit with the fully developed RREA mechanism, which corresponds to high‐potential leader models. The majority of the GBM‐measured TGFs can be best fit if the source altitude is below 15 km and 70% of events best fit by leader models cannot be satisfactorily modeled unless a tilted photon beam is used. For several spectrally soft TGFs, the tilted beam low‐potential leader model can best fit the data.

show abstract

A simulation study on the electric field spectral dependence of thunderstorm ground enhancements and gamma ray glows

Cited by 16 publications

References 30 publications

Gamma Ray Glow Observations at 20‐km Altitude

Gamma Ray Glow Observations at 20‐km Altitude

Determining Electric Fields in Thunderclouds With the Radiotelescope LOFAR

Analysis of Individual Terrestrial Gamma‐Ray Flashes With Lightning Leader Models and Fermi Gamma‐Ray Burst Monitor Data

Contact Info

Product

Resources

About