S. Mancuso and L. Abbo (2004, A&A, 415, L17) Okamoto Takenori
description
Transcript of S. Mancuso and L. Abbo (2004, A&A, 415, L17) Okamoto Takenori
Bifurcation of the metric type II radio emission associated with the giant
solar flare of April 2 2001
S. Mancuso and L. Abbo(2004, A&A, 415, L17)
Okamoto Takenori
Abstract
• Bifurcation– on April 2 2001, X20 flare.– the radio emission lanes, which is very
rare• Model
– the interaction of a piston driven shock with a vertical current sheet
– the model replicates successfully the observed bifurcation
– the magnetic reconnection was triggered in the current sheet by the shock wave passage
bifurcation
bifurcation
type II burst
NiCT/HiRAS
streamer axis and CME
The axis of symmetry of the expanding bubble does not coincide with the streamer axis.
CME
roughly circular shape
SOHO/LASCO
ModelThe frequencies of the type II were emitted at the two intersections of the expanding shock surface with the streamer axis.
Model
• Radio bursts– selectively produced– in the densest parts (along streamer axes)– the strength of fast-mode shocks can be very
much enhanced
• The shock wave passage– triggers magnetic reconnection just above the
AR the ejection of a supermagnetosonic plasmoid another shock
CME fronts
CME/Linear fit
UVCS
DPS
LASCO
Second shock
second shock
Conclusions
• The bifurcation of the radio type II emission was produced by a curved fast shock surface intersecting a vertical current sheet above an AR.
• The shock wave may have triggered magnetic reconnection in the current sheet, causing the ejection of a second plasmoid.
• Redio emitting inward propagating shocks should occur more often.– The emission of the positively drifting lanes
fades quickly.