STATISTICS OF THERMAL PLASMA PARAMETERS AND NON-THERMAL X-RAY SPECTRA OF SOLAR FLARES WITH HELIOSEISMIC RESPONSE

Abstract

We present the results of statistical analysis of various thermal plasma parameters and non-thermal X-ray spectra of helioseismically active (producing “sunquakes”) solar flares of the 24th solar cycle up to February 2014. Two samples of flares are compared: with helioseismic activity in the form of sunquakes and a sample of flares without photospheric disturbances. The dependences of the considered flare parameters on the energy of helioseismic disturbances are also investigated. Quantitative parameters of solar flares are taken from the statistical work of the Global Energetics series by Markus Ashwanden in 2014–2019. We consider thermodynamic plasma parameters derived from the analysis of RHESSI X-ray spectra and differential emission measure (from AIA EUV images), as well as the characterization of non-thermal X-ray spectra from RHE-SSI. Statistical analysis confirmed that helioseismically active solar flares are characterized by significantly larger fluxes of non-thermal X-ray emission compared to flares without photospheric perturbations. A good linear relationship between helioseismic energy and the total flux of non-thermal X-ray radiation and the total energy of accelerated electrons is found. It is shown that the power-law index of the nonthermal X‑ray spectrum is not the parameter by which one can separate the two groups of flares under consideration. The analysis of the X-ray thermal spectra shows a slight difference between the flares with the sunsets.