ON THE ROLE OF THE LARGE-SCALE MAGNETIC RECONNECTION IN THECORONAL HEATING

摘要

When an active region emerges, its magnetic field reconnectsrnwith the preexisting field. This localized reconnectionrnmay affect magnetic connectivity far away from thernemerging region. In some cases, the entire corona readjustsrnits magnetic connectivity because of changes introducedrnby the emerging flux. We propose that such largescalernreconnection, triggered by localized changes in thernmagnetic connectivity, may play a role in coronal heating.rnTo demonstrate the validity of this mechanism, wernstudy the evolution of an emerging active region NOAArn8131. Using SoHO/MDI full disk magnetograms andrnYohkoh/SXT data, we show that as the magnetic fieldrnemerges the surrounding corona increases its brightnessrnand temperature. The coronal enhancement in brightnessrnconsists of two components: loop-like structures and arndiffuse "cloud." Several days later, SXT data show distinctrnloops connecting the fully developed active regionrn8131 with magnetic flux outside the area of emergence.rnWe interpret these observations as a signature of coronalrnheating due to a large-scale reconnection process.