Scattering by whistler-mode waves during a quiet period perturbed by substorm activity

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378289%3A_____%2F21%3A00541808" target="_blank" >RIV/68378289:_____/21:00541808 - isvavai.cz</a>

Result on the web

<a href="https://www.sciencedirect.com/science/article/pii/S1364682620302741" target="_blank" >https://www.sciencedirect.com/science/article/pii/S1364682620302741</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.jastp.2020.105471" target="_blank" >10.1016/j.jastp.2020.105471</a>

Result language

angličtina

Original language name

Scattering by whistler-mode waves during a quiet period perturbed by substorm activity

Original language description

We study the dynamics of radiation belt electrons during a 10-day quiet period perturbed by substorm activity and preceding a high-speed stream (HSS), aiming at a global description of the radiation belts in L-shell, L in [2, 6], and energy [0.1, 10] MeV. We combine Van Allen Probes observations and Fokker-Planck numerical simulations of pitch-angle diffusion. The Fokker-Planck model uses event-driven pitch angle diffusion coefficients from whistler-mode waves, built from the wave properties and the ambient plasma density measurements from the Van Allen Probes. We first find this event has some similar characteristics to regular quiet times previously studied: a widely extended plasmasphere within which we observe strong and varying whistler-mode waves. These ambient conditions lead to strong pitch-angle scattering, which contributes to the creation of a wide slot region as well as a significant decay of the outer radiation belts, which are observed and qualitatively well simulated. In addition, we find the substorm activity causes short duration (within ? 4h) decay of the plasma density and a lowering amplitude of the whistler-mode waves within the plasmasphere, both causing opposite effects in terms of pitch angle diffusion. This leads to a diminution of pitch-angle diffusion at the time of the main substorm activity. Conversely, whistler-mode waves become enhanced in the time periods between the substorm injections. All effects cumulated, we find an enhancement of pitch angle diffusion by whistler-mode waves above L-4.7 during the 10-day period. This directly relates to the combination of quietness and substorm activity which allows pitch angle diffusing of up to 1 MeV electrons in the outer belt. Relativistic electrons of 1?2 MeV remain trapped in the outer belt, from L-4.7 to L-5.2, forming, in both the observations and the simulations, a distinct pocket of remnant electrons.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10305 - Fluids and plasma physics (including surface physics)

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2021

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Journal of Atmospheric and Solar-Terrestrial Physics

ISSN

1364-6826

e-ISSN

1879-1824

Volume of the periodical

215

Issue of the periodical within the volume

April

Country of publishing house

GB - UNITED KINGDOM

Number of pages

14

Pages from-to

105471

UT code for WoS article

000633030300001

EID of the result in the Scopus database

2-s2.0-85101393206