Multi-wavelength study of the ignition and propagation of a coronal shock wave

B. Vrsnak

J. Magdalenic, A. Veronig, M. Temer, A. Warmuth

We present multi-wavelength observations of the coronal shock wave ignited by the close-to-limb two-ribbon X4-flare of 3 November 2003. The kinematics of the Moreton wave, mesured utilizing the Kanzelhohe Observatory H-alpha filtergrams, indicates that the perturbation was launched at the peak of the impulsive hard X-ray burst observed by RHESSI, and the peak of the associated microwave burst recorded by Ondrejov Observatory spectrograph. This is supported by the combined analysis of the dynamic spectrum of the type II radio burst recorded by OSRA-AIP and PHOENIX-ETH-Zurich, and the Nancay Radioheliographic positions of the associated radio sources. Kinematics of the flare-associated CME, inferred employing the H-alpha and LASCO-SOHO data, clearly excludes the possibility that the shock was driven by the ejection itself, as well as the possibility that the type II burst was excited at the termination shock in the reconnection outflow below the erupting flux rope. The observations are interpreted in terms of the pressure-pulse mechanism. The shock-formation time is estimated to be 2-3 minutes, during which the perturbation travelled around 100 Mm in the horizontal direction and 200 Mm in the vertical direction.

The data recorded over the whole spectral range, from hard X-rays to metric-wavelengths, provide a unique oportunity to get a detailed insight and discuss processes related to the ignition of the perturbation, its steepening into the shock, and the space/time evolution of the shock.