Spectrum of Solar Type I Continuum Noise Storm in the 50-80 MHz Band and Plasma Characteristics in the Associated Source Region

Abstract

Continuum observations of a solar noise storm in the frequency range of 50-80 MHz observed with the Gauribidanur radio spectrograph during 2000 September 26 and 27 are presented here. The radio spectral index of the noise storm continuum in the 50-80 MHz band is found to be ~3.65 during the above period. The noise storm continuum radiation is explained as a consequence of the nonthermal, plasma emission mechanism. The beam density of suprathermal electrons is estimated for the coronal plasma near the source region of storm radiation. Supplementary evidence for the density estimate is provided by way of analyzing the imaging data from the Soft X-Ray Telescope on board the Yohkoh spacecraft, and the Large Angle and Spectrometric Coronagraph, Michaelson-Doppler Imager, and Extreme-ultraviolet Imaging Telescope on board the SOHO spacecraft.