Quasi-periodic processes in the flare loop generated by sudden temperature enhancements at loop footpoints

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60076658%3A12310%2F16%3A43890597" target="_blank" >RIV/60076658:12310/16:43890597 - isvavai.cz</a>

Výsledek na webu

<a href="http://www.aanda.org/articles/aa/abs/2016/06/aa27306-15/aa27306-15.html" target="_blank" >http://www.aanda.org/articles/aa/abs/2016/06/aa27306-15/aa27306-15.html</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/201527306" target="_blank" >10.1051/0004-6361/201527306</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Quasi-periodic processes in the flare loop generated by sudden temperature enhancements at loop footpoints

Popis výsledku v původním jazyce

Aims. During the impulsive flare phase, the plasma at the flare loop footpoints is rapidly heated by particle beams. In the present paper, we study processes that occur after this sudden heating in a two-dimensional magnetic loop. Methods. We adopt a 2D magnetohydrodynamic (MHD) model, in which we solve a full set of the ideal time-dependent MHD equations by means of the FLASH code, using the adaptive mesh refinement (AMR) method. Periods in the processes are estimated by the wavelet analysis technique. Results. We consider a model of the solar atmosphere with a symmetric magnetic loop. The length of this loop in the corona is approximately 21 : 5 Mm. At both loop footpoints, at the transition region, we initiate the Gaussian temperature (pressure) perturbation with the maximum temperature 14, 7, or 3.5 times higher than the unperturbed temperature. In the corona, the perturbations produce supersonic blast shocks with the Mach number of about 1.1, but well below Alfven velocities. We consider cases with the same perturbations at both footpoints (symmetric case) and one with different perturbations (asymmetric case). In the symmetric case, the shocks move along both loop legs upwards to the top of the loop, where they interact and form a transient compressed region. Then they continue in their motion to the transition region at the opposite side of the loop, where they are reflected upwards, and so on. At the top of the loop, the shock appears periodically with the period of about 170 s. In the loop legs during this period, a double peak of the plasma parameters, which is connected with two arrivals of shocks, is detected: firstly, when the shock moves up and then when the shock, propagating from the opposite loop leg, moves down. Increasing the distance of the detection point in the loop leg from the top of the loop, the time interval between these shock arrivals increases. Thus, at these detection points, the processes with shorter periods can be detected.

Název v anglickém jazyce

Quasi-periodic processes in the flare loop generated by sudden temperature enhancements at loop footpoints

Popis výsledku anglicky

Aims. During the impulsive flare phase, the plasma at the flare loop footpoints is rapidly heated by particle beams. In the present paper, we study processes that occur after this sudden heating in a two-dimensional magnetic loop. Methods. We adopt a 2D magnetohydrodynamic (MHD) model, in which we solve a full set of the ideal time-dependent MHD equations by means of the FLASH code, using the adaptive mesh refinement (AMR) method. Periods in the processes are estimated by the wavelet analysis technique. Results. We consider a model of the solar atmosphere with a symmetric magnetic loop. The length of this loop in the corona is approximately 21 : 5 Mm. At both loop footpoints, at the transition region, we initiate the Gaussian temperature (pressure) perturbation with the maximum temperature 14, 7, or 3.5 times higher than the unperturbed temperature. In the corona, the perturbations produce supersonic blast shocks with the Mach number of about 1.1, but well below Alfven velocities. We consider cases with the same perturbations at both footpoints (symmetric case) and one with different perturbations (asymmetric case). In the symmetric case, the shocks move along both loop legs upwards to the top of the loop, where they interact and form a transient compressed region. Then they continue in their motion to the transition region at the opposite side of the loop, where they are reflected upwards, and so on. At the top of the loop, the shock appears periodically with the period of about 170 s. In the loop legs during this period, a double peak of the plasma parameters, which is connected with two arrivals of shocks, is detected: firstly, when the shock moves up and then when the shock, propagating from the opposite loop leg, moves down. Increasing the distance of the detection point in the loop leg from the top of the loop, the time interval between these shock arrivals increases. Thus, at these detection points, the processes with shorter periods can be detected.

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

BN - Astronomie a nebeská mechanika, astrofyzika

OECD FORD obor

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Projekt

<a href="/cs/project/GA16-13277S" target="_blank" >GA16-13277S: Magnetoakustické vlny v diagnostice plazmatu ve sluneční koróně: nový pohled prostřednictvím pokročilých numerických simulací</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2016

Kód důvěrnosti údajů

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

Název periodika

Astronomy &amp; Astrophysics

ISSN

0004-6361

e-ISSN

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Svazek periodika

590

Číslo periodika v rámci svazku

JUN 2016

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

9

Strana od-do

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Kód UT WoS článku

000378106800033

EID výsledku v databázi Scopus

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