1. 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
S. Mancuso and L. Abbo (2004, A&A, 415, L17)
Okamoto Takenori

2. Abstract Bifurcation Model 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

3. bifurcation
bifurcation
type II burst
NiCT/HiRAS

4. streamer axis and CME
The axis of symmetry of the expanding bubble does not
coincide with the streamer axis.

5. CME
roughly circular shape
SOHO/LASCO

6. Model
The frequencies of the type II were emitted at the two intersections
of the expanding shock surface with the streamer axis.

7. Model Radio bursts The shock wave passage 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

8. CME fronts
CME/Linear fit
LASCO
UVCS
DPS

9. Second shock
second shock

10. 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.