SUMER Observations of Heating and Cooling of Coronal Loops
Abstract
Hot-loop transient events observed by SUMER in hot EUV lines are known to trigger loop oscillations, as reported by Kliem et al. [1] and Wang et al. [2], [3]. Apart from the inference of physical parameters in the solar corona, these observations also carry the signatures of heating and cooling of coronal loops. We present the light curves for various highly-ionized ions which were simultaneously observed during and after the trigger. Even though the majority of SUMER events occur on sub-flare level, it is clear that the heating is impulsive and drives the plasma to a very high temperature of up to 10 MK within minutes. During the cooling phase, however, we find the plasma in gradually decreasing ionization stages which implies that the entire loop system involved in such events is basically in the isothermal state. Such events may also help in our understanding of mass supply and energy transport in the corona.
- Publication:
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SOHO 13 Waves, Oscillations and Small-Scale Transients Events in the Solar Atmosphere: Joint View from SOHO and TRACE
- Pub Date:
- January 2004
- Bibcode:
- 2004ESASP.547..333C