Slow halo CMEs with shock signatures

Details Slow halo CMEs with shock signatures Slow halo CMEs with shock signatures

Apr 2006

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006a%26a...449..359p&link_type=abstract

Astronomy and Astrophysics, Volume 449, Issue 1, April I 2006, pp.359-367

Astronomy and Astrophysics

Astrophysics

9

Scientific paper

Context: .In the solar corona, shocks are formed when the speed of a disturbance exceeds the local magnetosonic speed. In the active region corona the Alfvén speed can drop to a few hundred km s-1, but globally it is much higher. There has been a long debate on whether the shocks responsible for type II bursts are created by bow shocks in front of coronal mass ejections (CMEs), shocks in the flanks of CMEs, or by flare (blast) waves.Aims.We study the alternative explanations for type II bursts in events where we have a slow CME, flare(s), and associated type II burst emission.Methods.We use multi-wavelength observations to analyse the height-time evolution of CMEs and compare it with the evolution of shock signatures in radio and EUV.Results.Three flare-associated halo-type CME events were observed on October 30, 2004. Velocity estimates (260, 325, and 920 km s-1) from the first plane-of-the-sky CME leading front observations suggested that the first two were very slow compared to halo CMEs, on average. The CMEs were associated with flares (M 4.2, X1.2, and M 5.9) and each event was also associated with coronal (metric) type II emission that is known to be a signature of a propagating shock front. After the flare starts, loop displacements and large-scale dimmings were observed in EUV. The two slow halo CMEs started as filament eruptions, but the CME velocities and/or bulk motions were affected at the times of flares. We find support for the idea that the cause of metric type II bursts in these two events is flare-related. The later CME velocity changes (acceleration around 4-5 solar radii) could also be explained by eruptions associated with later flares. The repeating homologous flare-halo CME events indicate a restoration of the same large-scale structures within 5-6 h.

Affiliated with

Also associated with

No associations

Rating

Slow halo CMEs with shock signatures does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Slow halo CMEs with shock signatures, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Slow halo CMEs with shock signatures will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1156302