The Dynamics of High-Temperature Plasma in the Solar Corona according to SPIRIT Observations in Mg XII 8.42 Å Line

Abstract

The spatial-distribution dynamics of the hot coronal plasma with T ~ 10 MK during a period of high solar activity is studied. We analyze images of the NOAA 9830 active region and its surroundings obtained during the second half of February 2002 with the SPIRIT spectroheliograph in the Mg XII 8.42-Å line and simultaneously on the SOHO satellite with the EIT instrument and on the TRACE satellite in the 195-Å channel. As shown by a multiwavelength analysis, a high-temperature plasma is concentrated in the corona near the apices of magnetic loops, it has long lifetimes (up to several days), and its dynamics is complex and bears no direct relation to flare activity. During the flares, conspicuous increases are observed in the X-ray flux and the emission measure for temperatures of ~ 5-15 MK. Our analyses of the time variations in emission during a flare suggest that hot plasma is heated by fluxes of accelerated electrons.