High-frequency reverse drift bursts in 2012-2014 solar flares

0452726 - ASÚ 2016 RIV HR eng J - Journal Article
Jiřička, Karel - Karlický, Marian
High-frequency reverse drift bursts in 2012-2014 solar flares.
Central European Astrophysical Bulletin. Roč. 39, č. 1 (2015), s. 59-64. ISSN 1845-8319.
[Hvar Astrophysical Colloquium /13./. Hvar, 22.09.2014-26.09.2014]
R&D Projects: GA ČR GAP209/12/0103
Institutional support: RVO:67985815
Keywords : Sun * flares * radio emission
Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

During observations by the Ondřejov high-time resolution 0.8-2.0 GHz radio spectrograph in years 2012-2014, 33 high-frequency reverse drift bursts with frequency drift less than 500 MHz s-1 were found. In 23 cases these bursts were observed before the GOES flare maximum, while the remaining 10 after this GOES maximum. Using the Aschwanden's density model of the solar atmosphere and assuming the radio emission on the harmonic plasma frequency, the corresponding velocities of the agents generating these bursts are less than 7000 km s-1. These velocities are too slow for electron beams, therefore we propose that these bursts are generated by thermal conduction fronts or by magnetohydrodynamic shocks.
Permanent Link: http://hdl.handle.net/11104/0253629