Influence of the angular scattering of electrons on the runaway
threshold in air

J 2016

Influence of the angular scattering of electrons on the runaway threshold in air

CHANRION, Olivier, Zdeněk BONAVENTURA, Anne BOURDON a Torsten NEUBERT

Základní údaje

Originální název

Influence of the angular scattering of electrons on the runaway threshold in air

Název česky

Vliv úhlového rozptylu elektronů na práh pro ubíhající elektrony

Autoři

CHANRION, Olivier (250 Francie), Zdeněk BONAVENTURA (203 Česká republika, garant, domácí), Anne BOURDON (250 Francie) a Torsten NEUBERT (208 Dánsko)

Vydání

Plasma Physics and Controlled Fusion, Institute of Physics, 2016, 0741-3335

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10305 Fluids and plasma physics

Stát vydavatele

Velká Británie a Severní Irsko

Utajení

není předmětem státního či obchodního tajemství

Odkazy

URL

Impakt faktor

Impact factor: 2.392

Kód RIV

RIV/00216224:14310/16:00087786

Organizační jednotka

Přírodovědecká fakulta

DOI

http://dx.doi.org/10.1088/0741-3335/58/4/044001

UT WoS

000371818600004

Klíčová slova anglicky

terrestrial gamma-ray flashes; runaway electrons; streamers; thunderstorms; angular scattering; lightning; thermal runaway

Štítky

AKR, rivok

Změněno: 6. 4. 2017 20:35, Ing. Andrea Mikešková

Anotace

V originále

The runaway electron mechanism is of great importance for the understanding of the generation of x- and gamma rays in atmospheric discharges. In 1991, terrestrial gamma-ray flashes (TGFs) were discovered by the Compton Gamma-Ray Observatory. Those emissions are bremsstrahlung from high energy electrons that run away in electric fields associated with thunderstorms. In this paper, we discuss the runaway threshold definition with a particular interest in the influence of the angular scattering for electron energy close to the threshold. In order to understand the mechanism of runaway, we compare the outcome of different Fokker–Planck and Monte Carlo models with increasing complexity in the description of the scattering. The results show that the inclusion of the stochastic nature of collisions smooths the probability to run away around the threshold. Furthermore, we observe that a significant number of electrons diffuse out of the runaway regime when we take into account the diffusion in angle due to the scattering. Those results suggest using a runaway threshold energy based on the Fokker–Planck model assuming the angular equilibrium that is 1.6 to 1.8 times higher than the one proposed by [1, 2], depending on the magnitude of the ambient electric field. The threshold also is found to be 5 to 26 times higher than the one assuming forward scattering. We give a fitted formula for the threshold field valid over a large range of electric fields. Furthermore, we have shown that the assumption of forward scattering is not valid below 1 MeV where the runaway threshold usually is defined. These results are important for the thermal runaway and the runaway electron avalanche discharge mechanisms suggested to participate in the TGF generation.

Návaznosti

GA15-04023S, projekt VaV

Název: Pokročilý výzkum kinetických procesů ve streamerových výbojích

Investor: Grantová agentura ČR, Pokročilý výzkum kinetických procesů ve streamerových výbojích

LO1411, projekt VaV

Název: Rozvoj centra pro nízkonákladové plazmové a nanotechnologické povrchové úpravy (Akronym: CEPLANT plus)

Investor: Ministerstvo školství, mládeže a tělovýchovy ČR, Rozvoj centra pro nízkonákladové plazmové a nanotechnologické povrchové úpravy

Citovat

CHANRION, Olivier, Zdeněk BONAVENTURA, Anne BOURDON a Torsten NEUBERT. Influence of the angular scattering of electrons on the runaway threshold in air. Plasma Physics and Controlled Fusion. Institute of Physics, 2016, roč. 58, č. 4, s. "nestrankovano", 9 s. ISSN 0741-3335. Dostupné z: https://dx.doi.org/10.1088/0741-3335/58/4/044001.

@article{1331616,
   author = {Chanrion, Olivier and Bonaventura, Zdeněk and Bourdon, Anne and Neubert, Torsten},
   article_number = {4},
   doi = {http://dx.doi.org/10.1088/0741-3335/58/4/044001},
   keywords = {terrestrial gamma-ray flashes; runaway electrons; streamers; thunderstorms; angular scattering; lightning; thermal runaway},
   language = {eng},
   issn = {0741-3335},
   journal = {Plasma Physics and Controlled Fusion},
   title = {Influence of the angular scattering of electrons on the runaway threshold in air},
   url = {http://iopscience.iop.org/article/10.1088/0741-3335/58/4/044001},
   volume = {58},
   year = {2016}
}

TY  - JOUR
ID  - 1331616
AU  - Chanrion, Olivier - Bonaventura, Zdeněk - Bourdon, Anne - Neubert, Torsten
PY  - 2016
TI  - Influence of the angular scattering of electrons on the runaway threshold in air
JF  - Plasma Physics and Controlled Fusion
VL  - 58
IS  - 4
SP  - "nestrankovano"
EP  - "nestrankovano"
PB  - Institute of Physics
SN  - 07413335
KW  - terrestrial gamma-ray flashes
KW  - runaway electrons
KW  - streamers
KW  - thunderstorms
KW  - angular scattering
KW  - lightning
KW  - thermal runaway
UR  - http://iopscience.iop.org/article/10.1088/0741-3335/58/4/044001
L2  - http://iopscience.iop.org/article/10.1088/0741-3335/58/4/044001
N2  - The runaway electron mechanism is of great importance for the understanding of the generation of x- and gamma rays in atmospheric discharges. In 1991, terrestrial gamma-ray flashes (TGFs) were discovered by the Compton Gamma-Ray Observatory. Those emissions are bremsstrahlung from high energy electrons that run away in electric fields associated with thunderstorms. In this paper, we discuss the runaway threshold definition with a particular interest in the influence of the angular scattering for electron energy close to the threshold. In order to understand the mechanism of runaway, we compare the outcome of different Fokker–Planck and Monte Carlo models with increasing complexity in the description of the scattering. The results show that the inclusion of the stochastic nature of collisions smooths the probability to run away around the threshold. Furthermore, we observe that a significant number of electrons diffuse out of the runaway regime when we take into account the diffusion in angle due to the scattering. Those results suggest using a runaway threshold energy based on the Fokker–Planck model assuming the angular equilibrium that is 1.6 to 1.8 times higher than the one proposed by [1, 2], depending on the magnitude of the ambient electric field. The threshold also is found to be 5 to 26 times higher than the one assuming forward scattering. We give a fitted formula for the threshold field valid over a large range of electric fields. Furthermore, we have shown that the assumption of forward scattering is not valid below 1 MeV where the runaway threshold usually is defined. These results are important for the thermal runaway and the runaway electron avalanche discharge mechanisms suggested to participate in the TGF generation.
ER  -

CHANRION, Olivier, Zdeněk BONAVENTURA, Anne BOURDON a Torsten NEUBERT. Influence of the angular scattering of electrons on the runaway threshold in air. \textit{Plasma Physics and Controlled Fusion}. Institute of Physics, 2016, roč.~58, č.~4, s.~''nestrankovano'', 9 s. ISSN~0741-3335. Dostupné z: https://dx.doi.org/10.1088/0741-3335/58/4/044001.

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