Seismology of the solar corona through observations of metric type IV radio burst emission

Abstract

We present metric radio observation of a transient. quasi-periodic type IV burst emission from the solar corona following the hard X-ray/H¦Á flare of November 23, 2000. The radio event lasted for about 121s, and the measured mean period was 14.7 ¡À 2.5s. The source region of the observed radio emission was found to be located at a height of 0.18 ¡À 0.03 Ro above the solar photosphere. The Alfven speed (V/sub A) at that location was estimated to be 1185 ¡À 181 kms/sup-1. Combined with the plasma density corresponding to the observing frequency (109 MHz), this gives a magnetic field (B) of 7.2 ¡À 1.1 G for the above region. We also estimated the speed of the disturbance propagating through the solar atmosphere in the aftermath of the flare, and is ¡Ü 755 kms/sup-1.