HR: 09:25h
AN: SH21A-06    [PDF]
TI: Radio Observations of Rapid Acceleration in a Slow Filament Eruption/Fast CME Event
AU: * Kundu, M R
EM: kundu@astro.umd.edu
AF: University of Maryland, Astronomy Department, University of Maryland,, College Park, MD 20742 United States
AU: White, S M
EM: white@astro.umd.edu
AF: University of Maryland, Astronomy Department, University of Maryland,, College Park, MD 20742 United States
AU: Garaimov, V I
EM: gvi@astro.umd.edu
AF: University of Maryland, Astronomy Department, University of Maryland,, College Park, MD 20742 United States
AU: Manoharan, P K
EM: mano@astro.umd.edu
AF: Catholic University of America, Department of Physics, Catholic University of America,, Washington, DC 20064 United States
AU: Subramanian, P
EM: psubrama@iucaa.ernet.in
AF: IUCAA, Inter-University Centre for Astronomy and Astrophysics, Pune, 411007 India
AU: Ananthakrishnan, S
EM: ananth@ncra.tifr.res.in
AF: TIFR-NCRA, National Centre for Radio Astrophysics, TIFR, Pune, 411007 India
AU: Janardhan, P
EM: jerry@prl.ernet.in
AF: PRL, Physical Research Laboratory, Astronomy & Astrophysics Division, Ahmedabad, 380009 India
AB: We discuss a filament eruption/coronal mass ejection (CME) associated flare event of GOES class M2.8 that occurred on November 17, 2001. This event was observed simultaneously by Nobeyama RadioHeliograph (NoRH) at 17 and 34 GHz and by the Giant Meterwave Radio Telescope (GMRT) in India at 1060 MHz. The flare occurred in active region 9704 at S18E41. NoRH observes the filament during its eruption both as a dark feature against the solar disk and a bright feature above the solar limb. The filament eruption shows a very gradual onset and then a rapid acceleration phase coincident with the launch of a fast halo CME. The flare on the disk in microwaves has a gradual rise, a broad maximum and a gradual decay. At 1060 MHz, its time profile had three impulsive peaks. The NoRH height--time plot of the filament shows a roughly constant gradual acceleration for an hour, followed by a very abrupt acceleration coincident with the impulsive phase of the associated flare. Soft X--ray images show heating in a long loop underneath the filament prior to the flare. The impulsive behavior of 1060 MHz emission combined with high brightness temperatures indicated the existence of nonthermal electrons in loops that clearly are not the same as the loops containing the microwave-emitting electrons. The latter are dominated by thermal bremsstrahlung and agree well with the EUV and soft X--ray loops. This study is consistent with recent findings that the rapid acceleration of flare--associated CMEs is closely tied to the impulsive phase of the flare. A trigger is required to cause the rapid acceleration to occur at the same time as the flare even though the two events are spatially well separated. We speculate that this trigger is provided by some kind of reconnection in the multiple flux systems that exist between the flaring active region and the erupting filament.
DE: 7513 Coronal mass ejections
DE: 7519 Flares
DE: 7534 Radio emissions
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting