Abstract Details
| Name: Pramod Kumar Affiliation: Jagan Nath University, Jaipur Conference ID: ASI2016_405 Title : Statistical analysis of thermal X-ray emission (> 13keV) observed from the X class Solar flares Authors and Co-Authors : 1. Raj Kumar Choudhary, Affiliation: Space Physics Laboratory, VSSC, ISRO, Trivandrum, India 2. Yogesh C. Bhatt Affiliation: Jagan Nath University, Jaipur 3. Yadvendra S. Shisodiya Affiliation: Jagan Nath University, Jaipur Abstract Type : Poster Abstract Category : Sun and the Solar System Abstract : We present a statistical analysis of thermal X-ray emission (>13 keV) of eight (08) X-class solar flares observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) space craft during 2002-2011. The temporal evolution of each flare in 3-6, 6-12, 12-25, 25-49, 49-100, and 100-250 keV energy bands were analyzed. We find that in most of the flares, there was a gradual rise of X-ray flux in 3-25 keV energy bands. The sudden rise of X-ray flux above ~ 25 keV was observable during the impulsive phase of the flare. This shows that the solar flare plasma has a distribution which in thermal and non-thermal in nature and originates from the thermal and non-thermal X-ray emissions. The cross over energy was found to exist above ~ 25 keV. Further, we carried spectral analysis of each flare using spectral model fitting method over the spectra with reduced chi-square (χ^2) < 3. The spectrum of each flare was divided in 1 minute interval to achieve statistical reliable X-ray spectra. The thermal and non-thermal components of the each spectrum were fitted with the isothermal and thick target models using OSPEX software (consisting CHIANTI and fit function data base). From the fitting, we obtained set of values of plasma temperature, emission measure and non thermal electron flux parameters. Finally we simulated set of plasma parameters using Monte Carlo method and fitted the plasma temperature histogram with the normal distribution function, emission measure and non-thermal electron flux histograms with the exponential distribution functions. We find that most probable plasma temperature lies in ~ 30 MK, emission measure lies in ~ 0-1 x 10^49 /cm3 and non-thermal electron flux lies in ~ 0-500 x 10^35/s bins. |