Anisotropic Radio-wave Scattering and the Interpretation of Solar Radio Emission Observations

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378289%3A_____%2F19%3A00523127" target="_blank" >RIV/68378289:_____/19:00523127 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.research.manchester.ac.uk/portal/files/160060006/Kontar_2019_ApJ_884_122.pdf" target="_blank" >https://www.research.manchester.ac.uk/portal/files/160060006/Kontar_2019_ApJ_884_122.pdf</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3847/1538-4357/ab40bb" target="_blank" >10.3847/1538-4357/ab40bb</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Anisotropic Radio-wave Scattering and the Interpretation of Solar Radio Emission Observations

Popis výsledku v původním jazyce

The observed properties (i.e., source size, source position, time duration, and decay time) of solar radio emission produced through plasma processes near the local plasma frequency, and hence the interpretation of solar radio bursts, are strongly influenced by propagation effects in the inhomogeneous turbulent solar corona. In this work, a 3D stochastic description of the propagation process is presented, based on the Fokker-Planck and Langevin equations of radio-wave transport in a medium containing anisotropic electron density fluctuations. Using a numerical treatment based on this model, we investigate the characteristic source sizes and burst decay times for Type III solar radio bursts. Comparison of the simulations with the observations of solar radio bursts shows that predominantly perpendicular density fluctuations in the solar corona are required, with an anisotropy factor of similar to 0.3 for sources observed at around 30 MHz. The simulations also demonstrate that the photons are isotropized near the region of primary emission, but the waves are then focused by large-scale refraction, leading to plasma radio emission directivity that is characterized by a half width at half maximum of about 40 degrees near 30 MHz. The results are applicable to various solar radio bursts produced via plasma emission.

Název v anglickém jazyce

Anisotropic Radio-wave Scattering and the Interpretation of Solar Radio Emission Observations

Popis výsledku anglicky

The observed properties (i.e., source size, source position, time duration, and decay time) of solar radio emission produced through plasma processes near the local plasma frequency, and hence the interpretation of solar radio bursts, are strongly influenced by propagation effects in the inhomogeneous turbulent solar corona. In this work, a 3D stochastic description of the propagation process is presented, based on the Fokker-Planck and Langevin equations of radio-wave transport in a medium containing anisotropic electron density fluctuations. Using a numerical treatment based on this model, we investigate the characteristic source sizes and burst decay times for Type III solar radio bursts. Comparison of the simulations with the observations of solar radio bursts shows that predominantly perpendicular density fluctuations in the solar corona are required, with an anisotropy factor of similar to 0.3 for sources observed at around 30 MHz. The simulations also demonstrate that the photons are isotropized near the region of primary emission, but the waves are then focused by large-scale refraction, leading to plasma radio emission directivity that is characterized by a half width at half maximum of about 40 degrees near 30 MHz. The results are applicable to various solar radio bursts produced via plasma emission.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10305 - Fluids and plasma physics (including surface physics)

Projekt

<a href="/cs/project/GJ17-06818Y" target="_blank" >GJ17-06818Y: Heliosférická pozorování s využitím k předpovídání kosmického počasí</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2019

Kód důvěrnosti údajů

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

Název periodika

Astrophysical Journal

ISSN

0004-637X

e-ISSN

—

Svazek periodika

884

Číslo periodika v rámci svazku

2

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

15

Strana od-do

122

Kód UT WoS článku

000501779300002

EID výsledku v databázi Scopus

2-s2.0-85075150167