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Analysis of the flare waves associated with the 3B/X3.8 flare of January 17, 2005

The flare wave associated with the 3B/X3.8 flare and coronal mass ejection (CME) of January 17, 2005 are studied using imaging data in the Hα and EUV spectral channels. Due to the high-cadence Hα observations from Kanzelhöhe Solar Observatory (KSO), a distinct Moreton wave can be identified in ˜ 40 Hα frames over a period of ˜ 7 minutes. The associated coronal EIT wave is identifiable in only one EUV frame and appears close to the simultaneously observed Moreton wave front, indicating that they are closely associated phenomena. Beside the morphology of the wave across the solar disc (covering an angular extend of ˜ 130°), the evolution in different directions is studied to analyse the influence of a coronal hole (CH) on the wave propagation. The Moreton wave shows a decelerating character which can be interpreted in terms of a freely propagating fast-mode MHD shock. The parts of the wave front moving towards the CH show a lower initial and mean speed, and a greater amount of deceleration than the segments moving into the undisturbed direction. This is interpreted as the tendency of high Alfvén velocity regions to influence the propagation of wave packets.

shock waves; Sun: chromosphere; Sun: corona; Sun: flares

Vol. 31 (2007): Proceedings of 8th Hvar Astrophysical Colloquium: "Dynamical Processes in the Solar Atmosphere"