The interaction of a plasmoid with a loop-top kernel

¹ Astronomický ústav AV ČR, Fričova 298, 25165 Ondřejov, Czech Republic
² Instytut Astronomiczny Uniwersytetu Wrocławskiego, Kopernika 11, 51-622 Wrocław, Poland e-mail: kolomans@astro.uni.wroc.pl

Received: 26 July 2007
Accepted: 22 August 2007

Abstract

Aims.We study the interaction between a downward moving plasmoid and a loop-top kernel recognized in the 30 November 2000 flare. Such an interaction is predicted by some numerical models of solar flares.

Methods.Using X-ray observations from Yohkoh and GOES, EUV observations from SOHO, and radio observations from Ondřejov, we perform multi-wavelength analysis of this interaction.

Results.The Yohkoh/SXT and SOHO/EIT images indicate that the growing flare loop with the loop-top kernel and the above-lying plasmoid were formed as a result of the interaction of two extended arcade-loops. While the flare loop was growing upwards, the plasmoid moved downwards with the velocity of about 16 km s^-1 and interacted with the loop-top kernel. Many details of this interaction are found, e.g., an increase of the X-ray and decimetric radio fluxes and an increase of the plasma temperature at the interaction site. Just after the coalescence of the plasmoid with the loop-top kernel, the 1–2 GHz pulsating radio structure and hard X-ray source above the coalescence site were observed. The analyzed temperature maps indicate flows of heated plasma around the plasmoid to the location of the X-ray and radio source. These observations are in agreement with predictions from numerical modelling.