Relative timings of MM-waves and associated M-waves solar bursts

Observations of type III bursts (starting frequencies 237 to 408 MHz) and meter-wave narrowband fine time (approx. 300 msec) structures obtained with high sensitivity and high time resolution were compared with millimeter (22 GHz) wavelength bursts obtained simultaneously. For the major time structure (approx. 1 sec) the differences observed in the peak time of the type III burst and the associated mm -lambda emission are in the range of + or - 1 sec. In most cases, the type III burst peaked later by approx. 500 msec compared to the associated mm-lambda bursts. These observed time delays, along with the starting frequency (237 MHz) of the type III bursts suggest that the type III emission should be at the fundamental. Acceleration of the electrons should be time dependent and the acceleration region should be located where the electron density is approx. 10 to the 9th power/cu cm. Narrowband m-lambda fine structures with duration up to approx. 200 msec were found to be often associated with mm-lambda time structures, and the difference in their peak times was about + or - 150 msec on the average. Also in most cases, the peaks of narrowband m-lambda fine time structures led the associated mm-lambda time structures by approx. 150 msec. These observed time differences are three times smaller than those observed in the case of the type III bursts and in majority of cases, of opposite sign. These average small differences and their sign can be accounted for, if the narrowband m-lambda fine structures are assumed to be due to processes of secondary acceleration, and source of acceleration region should be near the region where m-lambda fine structure is produced.