Spectral Association of the 7 August 1972 Solar Radio Burst with Particle Acceleration

Microwave burst data from the August 7,1972 event recorded on nine discrete frequencies between 245 and 35 000 MHz at the Sagamore Hill Radio Observatory (Figure 1) provide a basis for correlation studies (especially timing information) of the associated white light flare, the high energy particle emission, type II bursts, and many other phenomena. This is perhaps the first time that sufficient radio coverage (i.e., data above 10000 MHz) was available to obtain the spectral slope information (related to electron-energy distribution) which is inherent in this part of the spectrum. Heretofore, timing was related to burst flux density profile variations. Improved correlations resulted from shorter centimeter wavelength data which supplied more accurate timing information than that derived from Hα observations. The shape and intensity of the burst peak flux density spectrum has also been used for qualitative analysis of energetic particle and white light events. The ultimate good may possibly come from spectral analysis of the minute by minute variation of the burst microwave radiation spectral slope α (above fmax) in the area between 15 000 and 35 000 MHz. This may be used alone or in relation to the position of fmax where fmax is the frequency of burst maximum emission at a given time. This is basically our present investigation.