Abstract
An analysis of 40 solar flares observed with the Yohkoh satellite was carried out to investigate the temporal relationship between rapid hard and soft X-ray flaring. Using Bragg Crystal Spectrometer (BCS) and Hard X-ray Telescope (HXT) data it was found that in every event the Neupert effect occurred throughout most of the impulsive phase. The effect was weakest late in the impulsive phase. Soft X-ray Telescope (SXT) image sequences showed that this was simply the result of the soft X-ray emission from cooling sources dominating the BCS observed flux, and that all intense non-thermal bursts are temporally associated with impulsive soft X-ray brightenings. Furthermore, at the start of the impulsive phase of these flares the rate of change of the BCS soft X-ray flux was found to be proportional to the hard X-ray intensity. These results demonstrate a causal relationship between thermal and non-thermal emissions, consistent with the thick target model.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
