5:15 PM - 7:15 PM
[PEM11-P09] Statistical study of solar flares by using multiple Time-of-Flight methods observed with Fermi
Keywords:solar flare, particle acceleration
The solar flare is an explosive brightening phenomenon that occurs on the solar surface. Especially, Hard X-ray shows a significant increase during the impulsive phase, and short duration spike-like structures appeared in some flares. These spikes are known as made by electrons that precipitate directly to footpoints from the acceleration site. Aschwanden+1996 estimated the height of the acceleration site by using the Time-of-Flight (TOF) method that analyzes the lag-time between each energy Hard X-ray.
In our previous study, we accepted the TOF method repeatedly for some flares. Then we got indirect evidence of the time evolution of the acceleration site from TOF and the imaging data (JpGU2024 P-EM14 P05). However, a statistical study was not performed.
Therefore, we applied this analysis to all flares observed with Gamma-Ray Burst Monitor (GBM) onboard Fermi. This instrument performs trigger observation with a high temporal resolution of 64ms when X-ray and Gamma-ray flux are grown. In addition, nearly 2,000 flares have been observed since launch in 2008. We detected short duration spikes by removing long duration components by applying a low-pass filter, the same as in previous studies. As a result, we collected several spikes from a few percent of flares. In this talk, we will assume the tendency of the time evolution of the lag-times. Furthermore, we will discuss nonthermal features of these spikes such as duration and energy spectra.
In our previous study, we accepted the TOF method repeatedly for some flares. Then we got indirect evidence of the time evolution of the acceleration site from TOF and the imaging data (JpGU2024 P-EM14 P05). However, a statistical study was not performed.
Therefore, we applied this analysis to all flares observed with Gamma-Ray Burst Monitor (GBM) onboard Fermi. This instrument performs trigger observation with a high temporal resolution of 64ms when X-ray and Gamma-ray flux are grown. In addition, nearly 2,000 flares have been observed since launch in 2008. We detected short duration spikes by removing long duration components by applying a low-pass filter, the same as in previous studies. As a result, we collected several spikes from a few percent of flares. In this talk, we will assume the tendency of the time evolution of the lag-times. Furthermore, we will discuss nonthermal features of these spikes such as duration and energy spectra.