ON THE DISK Hα AND RADIO OBSERVATIONS OF THE 2003 OCTOBER 28 FLARE AND CORONAL MASS EJECTION EVENT

摘要

We present the evolution of the Hα and radio emissions seen by the Meudon Hα telescope and the Nancay radioheliograph, which are associated with the X17.2 flare and halo CME of 2003 October 28. The remarkable characteristic of this event is its spatial extent that it reached in a few minutes. At 164 MHz, radio images show that the emission covers the whole disk of the Sun and extends as far as 1.8 solar radius from the Sun's center. The radio emissions, the Moreton wave seen in Hα, and the CME all show a similar temporal and spatial development, and the three phenomena are likely to be related. We show that multifrequency radio imaging observations obtained at high cadence can accurately visualize the initial on-the-disk development of fast halo CMEs and also provide physical parameters such as their speed and angular expansion.