High-density Off-limb Flare Loops Observed by SDO

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F18%3A00497539" target="_blank" >RIV/67985815:_____/18:00497539 - isvavai.cz</a>

Výsledek na webu

<a href="http://hdl.handle.net/11104/0290095" target="_blank" >http://hdl.handle.net/11104/0290095</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3847/1538-4357/aae650" target="_blank" >10.3847/1538-4357/aae650</a>

Jazyk výsledku

angličtina

Název v původním jazyce

High-density Off-limb Flare Loops Observed by SDO

Popis výsledku v původním jazyce

On 2017 September 10, a prominent loop system appeared during the gradual phase of an X8.2 flare (SOL2017-09-10), visible in all passbands of SDO/AIA and in the white-light continuum of SDO/HMI. We investigate its electron density by taking into account all radiation processes in the flare loops, i.e., the Thomson continuum, hydrogen Paschen and Brackett recombination continua, as well as free–free continuum emission. We derive a quadratic function of the electron density for a given temperature and effective loop thickness. By absolutely calibrating SDO/HMI intensities, we convert the measured intensities into electron density at each pixel in the loops. For a grid of plausible temperatures between cool (6000 K) and hot (106 K) structures, the electron density is computed for representative effective thicknesses between 200 and 20,000 km. We obtain a relatively high maximum electron density, about 1013 cm‑3. At such high electron densities, the Thomson continuum is negligible and therefore one would not expect a significant polarization degree in dense loops. We conclude that the Paschen and Brackett recombination continua are dominant in cool flare loops, while the free–free continuum emission is dominant for warmer and hot loops.

Název v anglickém jazyce

High-density Off-limb Flare Loops Observed by SDO

Popis výsledku anglicky

On 2017 September 10, a prominent loop system appeared during the gradual phase of an X8.2 flare (SOL2017-09-10), visible in all passbands of SDO/AIA and in the white-light continuum of SDO/HMI. We investigate its electron density by taking into account all radiation processes in the flare loops, i.e., the Thomson continuum, hydrogen Paschen and Brackett recombination continua, as well as free–free continuum emission. We derive a quadratic function of the electron density for a given temperature and effective loop thickness. By absolutely calibrating SDO/HMI intensities, we convert the measured intensities into electron density at each pixel in the loops. For a grid of plausible temperatures between cool (6000 K) and hot (106 K) structures, the electron density is computed for representative effective thicknesses between 200 and 20,000 km. We obtain a relatively high maximum electron density, about 1013 cm‑3. At such high electron densities, the Thomson continuum is negligible and therefore one would not expect a significant polarization degree in dense loops. We conclude that the Paschen and Brackett recombination continua are dominant in cool flare loops, while the free–free continuum emission is dominant for warmer and hot loops.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2018

Kód důvěrnosti údajů

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

Název periodika

Astrophysical Journal

ISSN

1538-4357

e-ISSN

—

Svazek periodika

867

Číslo periodika v rámci svazku

2

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

10

Strana od-do

134

Kód UT WoS článku

000450221700001

EID výsledku v databázi Scopus

2-s2.0-85056699532