An altitude and distance correction to the source fluence distribution of TGFs

Nisi, Ragnhild Schrøder; Østgaard, Nikolai; Gjesteland, Thomas; Collier, A. B.

doi:10.1002/2014ja019817

Cited by 10 publications

(10 citation statements)

References 27 publications

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“…This means that the TGFs would have to propagate through more air to reach RHESSI and thus be attenuated more. This is consistent with the work done in Nisi et al (), where they compared TGFs from the first and second RHESSI catalogs (Gjesteland et al, ; Grefenstette et al, ). They find that TGFs from the second catalog (and thus generally weaker observationally) have a larger portion originating at higher tropopause pressure (which again translates to a higher absolute latitude, but lower cloud top altitude).…”

Section: Resultssupporting

confidence: 91%

Observationally Weak TGFs in the RHESSI Data

et al. 2019

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Terrestrial gamma ray flashes (TGFs) are sub‐millisecond bursts of high energetic gamma radiation associated with intracloud flashes in thunderstorms. In this paper we use the simultaneity of lightning detections by World Wide Lightning Location Network to find TGFs in the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) data that are too faint to be identified by standard search algorithms. A similar approach has been used in an earlier paper, but here we expand the data set to include all years of RHESSI + World Wide Lightning Location Network data and show that there is a population of observationally weak TGFs all the way down to 0.22 of the RHESSI detection threshold (three counts in the detector). One should note that the majority of these are “normal” TGFs that are produced further away from the subsatellite point (and experience a 1/ r 2 effect) or produced at higher latitudes with a lower tropoause and thus experience increased atmospheric attenuation. This supports the idea that the TGF production rate is higher than currently reported. We also show that compared to lightning flashes, TGFs are more partial to ocean and coastal regions than over land.

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Section: Resultssupporting

confidence: 91%

Observationally Weak TGFs in the RHESSI Data

et al. 2019

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“…This value is consistent with the maximum distance between the TGF source positions and Fermi footprints given using WWLLN (World Wide Lightning Location Network) associations (Briggs et al, 2013;Fitzpatrick et al, 2014). We can also determine R lim R = 694 km, which is reasonably close to the largest distance found between RHESSI's position and the WWLLN match of the TGF source location (Nisi et al, 2014). Using the simulated photon flux and time profiles at 490 km altitude, we can estimate R lim XG = 648 km for AGILE-MCAL.…”

Section: Estimating Tgf and Teb Detection Ratessupporting

confidence: 86%

TARANIS XGRE and IDEE detection capability of terrestrial gamma-ray flashes and associated electron beams

Sarria

Lebrun

Blelly

et al. 2017

Geosci. Instrum. Method. Data Syst.

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Abstract. With a launch expected in 2018, the TARANIS microsatellite is dedicated to the study of transient phenomena observed in association with thunderstorms. On board the spacecraft, XGRE and IDEE are two instruments dedicated to studying terrestrial gamma-ray flashes (TGFs) and associated terrestrial electron beams (TEBs). XGRE can detect electrons (energy range: 1 to 10 MeV) and X-and gammarays (energy range: 20 keV to 10 MeV) with a very high counting capability (about 10 million counts per second) and the ability to discriminate one type of particle from another. The IDEE instrument is focused on electrons in the 80 keV to 4 MeV energy range, with the ability to estimate their pitch angles.Monte Carlo simulations of the TARANIS instruments, using a preliminary model of the spacecraft, allow sensitive area estimates for both instruments. This leads to an averaged effective area of 425 cm 2 for XGRE, used to detect Xand gamma-rays from TGFs, and the combination of XGRE and IDEE gives an average effective area of 255 cm 2 which can be used to detect electrons/positrons from TEBs. We then compare these performances to RHESSI, AGILE and Fermi GBM, using data extracted from literature for the TGF case and with the help of Monte Carlo simulations of their mass models for the TEB case.Combining this data with the help of the MC-PEPTITA Monte Carlo simulations of TGF propagation in the atmosphere, we build a self-consistent model of the TGF and TEB detection rates of RHESSI, AGILE and Fermi. It can then be used to estimate that TARANIS should detect about 200 TGFs yr −1 and 25 TEBs yr −1 .

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“…The radial distance of 200 km is chosen because it corresponds approximately to the maximum probability of receiving a TGF photon when considering the variation of photon density with radial distance from the source and the probability for a low‐orbit satellite to be at a given radial distance from a TGF source [ Celestin and Pasko , ]. Additionally, this radial distance corresponds well to typical radial distances of TGF observations by Fermi [e.g., Briggs et al , , Figure 8], AGILE [ Marisaldi et al , , ], and RHESSI [e.g., Nisi et al , , Figure 5]. Figure shows the data presented in Table assuming that 10 11 to 10 12 photons with energies greater than 10 keV are produced by a leader forming a potential drop of 5 MV.…”

Section: Resultsmentioning

confidence: 99%

Variability in fluence and spectrum of high‐energy photon bursts produced by lightning leaders

Célestin

Pasko

2015

JGR Space Physics

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In this paper, we model the production and acceleration of thermal runaway electrons during negative corona flash stages of stepping lightning leaders and the corresponding terrestrial gamma ray flashes (TGFs) or negative cloud‐to‐ground (−CG) lightning‐produced X‐ray bursts in a unified fashion. We show how the source photon spectrum and fluence depend on the potential drop formed in the lightning leader tip region during corona flash and how the X‐ray burst spectrum progressively converges toward typical TGF spectrum as the potential drop increases. Additionally, we show that the number of streamers produced in a negative corona flash, the source electron energy distribution function, the corresponding number of photons, and the photon energy distribution and transport through the atmosphere up to low‐orbit satellite altitudes exhibit a very strong dependence on this potential drop. This leads to a threshold effect causing X‐rays produced by leaders with potentials lower than those producing typical TGFs extremely unlikely to be detected by low‐orbit satellites. Moreover, from the number of photons in X‐ray bursts produced by −CGs estimated from ground observations, we show that the proportionality between the number of thermal runaway electrons and the square of the potential drop in the leader tip region during negative corona flash proposed earlier leads to typical photon fluences on the order of 1 ph/cm2 at an altitude of 500 km and a radial distance of 200 km for intracloud lightning discharges producing 300 MV potential drops, which is consistent with observations of TGF fluences and spectra from satellites.

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An altitude and distance correction to the source fluence distribution of TGFs

Cited by 10 publications

References 27 publications

Observationally Weak TGFs in the RHESSI Data

Observationally Weak TGFs in the RHESSI Data

TARANIS XGRE and IDEE detection capability of terrestrial gamma-ray flashes and associated electron beams

Variability in fluence and spectrum of high‐energy photon bursts produced by lightning leaders

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