Heating manifestations at the onset of the 29 June 2012 flare

Abstract

Analysis of GOES data for the SOL2012-06-29T04:09 flare, class C4.6, shows a thermal character of the energy release for several minutes before the impulsive stage. Plasma heating to temperatures above 10 MK leads to the appearance of plasma jets along open field lines and in large loops. This work examines the relationship between the heated plasma and the flare structure and its dynamics, using observations in the X-ray, extreme ultraviolet (EUV), and radio-wave ranges. Particular attention is drawn to the detection of narrow-band fine temporal structures of radio emission before and after the impulsive stage of the flare in dynamic spectra. In the initial stage, broadband pulses in the decimeter range are observed which can be associated with the formation of thermal fronts in the jets. A series of super-bright drifting bursts in the centimeter range occurs after the end of the impulsive energy release in the flare kernel. Using data from the Siberian Solar Radio Telescope (5.7 GHz), we managed to localize the position of the source of the fine structure of drifting bursts at the remote footpoint of the large-scale flare loop.

Keywords

• sun
• fine temporal structure
• heating mechanisms
• microwave bursts
• coherent emission
• thermal front
• neupert effect