Correlation between the Sharp Variation of the Transport Rate of Magnetic Helicity and Solar Eruptive Events

Abstract

In this Letter we report a close relationship between the variations of the transport rate of magnetic helicity (dH/dt) and a microwave burst. The latter may be regarded as a prompt signal of nonthermal energetic particles originating from the magnetic reconnection during solar flaring events. We analyze the observations of magnetograms of MDI/SOHO and SOT/Hinode and the high-cadence microwave observation at 2.84 GHz obtained by the Chinese Solar Broadband Radiospectrometer (SBRS/Huairou) of a flare/CME event that occurred in NOAA Active Region 10930 on 2006 December 13. We find that there is a sharp jump of dH/dt around the onset and quench of a microwave burst at a frequency of 2.84 GHz: the rate of dH/dt changes from negative to positive around the start of the eruption and recovers to negative when the eruption stopped. Furthermore, the temporal profile of dH/dt is consistent with that of a microwave burst. These results indicate that sharp variations of dH/dt are closely related to the solar eruption.