Number of the records: 1
Thermal Fronts in Solar Flares
- 1.
SYSNO ASEP 0452718 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Thermal Fronts in Solar Flares Author(s) Karlický, Marian (ASU-R) RID, ORCID Source Title Astrophysical Journal - ISSN 0004-637X
Roč. 814, č. 2 (2015), 153/1-153/7Number of pages 7 s. Publication form Print - P Language eng - English Country US - United States Keywords plasmas ; Sun flares ; radio radiation Subject RIV BN - Astronomy, Celestial Mechanics, Astrophysics R&D Projects GAP209/12/0103 GA ČR - Czech Science Foundation (CSF) Institutional support ASU-R - RVO:67985815 UT WOS 000371463200022 EID SCOPUS 84948733380 DOI 10.1088/0004-637X/814/2/153 Annotation We studied the formation of a thermal front during the expansion of hot plasma into colder plasma. We used a three-dimensional electromagnetic particle-in-cell model that includes inductive effects. In early phases, in the area of the expanding hot plasma, we found several thermal fronts, which are defined as a sudden decrease of the local electron kinetic energy. The fronts formed a cascade. Thermal fronts with higher temperature contrast were located near plasma density depressions, generated during the hot plasma expansion. The formation of the main thermal front was associated with the return-current process induced by hot electron expansion and electrons backscattered at the front. A part of the hot plasma was trapped by the thermal front while another part, mainly with the most energetic electrons, escaped and generated Langmuir and electromagnetic waves in front of the thermal front, as shown by the dispersion diagrams. Considering all of these processes and those described in the literature, we show that anomalous electric resistivity is produced at the location of the thermal front. Thus, the thermal front can contribute to energy dissipation in the current-carrying loops of solar flares. We estimated the values of such anomalous resistivity in the solar atmosphere together with collisional resistivity and electric fields. We propose that the slowly drifting reverse drift bursts, observed at the beginning of some solar flares, could be signatures of the thermal front. Workplace Astronomical Institute Contact Radka Svašková, bibl@asu.cas.cz, Tel.: 323 620 326 Year of Publishing 2017
Number of the records: 1