MICROWAVE QUASI-PERIODIC PULSATIONS IN MULTI-TIMESCALES ASSOCIATED WITH A SOLAR FLARE/CME EVENT

Abstract

Microwave observations of quasi-periodic pulsations (QPP) in multi-timescales\nare confirmed to be associated with an X3.4 flare/CME event at Solar Broadband\nRadio Spectrometer in Huairou (SBRS/Huairou) on 13 December 2006. It is most\nremarkable that the timescales of QPPs are distributed in a broad range from\nhecto-second (very long period pulsation, VLP, the period P>100 s), deca-second\n(long period pulsation, LPP, 10<P<100 s), few seconds (short period pulsation,\nSPP, 1<P<10 s), deci-second (slow-very short period pulsation, slow-VSP,\n0.1<P<1.0 s), to centi-second (fast-very short period pulsation, fast-VSP,\nP<0.1 s), and forms a broad hierarchy of timescales. The statistical\ndistribution in logarithmic period-duration space indicates that QPPs can be\nclassified into two groups: group I includes VLP, LPP, SPP and part of\nslow-VSPs distributed around a line approximately; group II includes fast-VSP\nand most of slow-VSP dispersively distributed away from the above line. This\nfeature implies that the generation mechanism of group I is different from\ngroup II. Group I is possibly related with some MHD oscillations in magnetized\nplasma loops in the active region, e.g., VLP may be generated by standing slow\nsausage mode coupling and resonating with the underlying photospheric 5-min\noscillation, the modulation is amplified and forms the main framework of the\nwhole flare/CME process; LPP, SPP, and part of slow-VSPs are most likely to be\ncaused by standing fast modes or LRC-circuit resonance in current-carrying\nplasma loops. Group II is possibly generated by modulations of resistive\ntearing-mode oscillations in electric current-carrying flaring loops.\n