An analysis of the solar energetic particle propagation of the maximum solar flare on 24th solar cycle.

Abstract

This research studies the propagation of solar energetic particles (SEPs) from the strongest solar flare in the 24th solar cycle. The particle propagation was simulated for the solar event on September 6, 2017. The X-ray class of the selected solar event is X9.3, the solar flare position on the sun is S10W30, and the solar wind speed is 575 km/s at 12:02 UTC for 17 minutes. We used data from the Solar Isotope Spectrometer instrument on ACE (Advanced Composition Explorer) spacecraft. The propagation of the solar energetic particles was simulated by the Ruffolo (1995, 1998) transport equation and solved by finite different method. The injection duration was estimated by the curve-fitting technique of piecewise-linear least square with the simulated results and the data from spacecraft. The fitting results between the spacecraft data and the simulation results found the mean free path roughly constant for each particle. The element with a small atomic mass such as helium, carbon, oxygen and nitrogen have the larger mean free path as compare to the high atomic mass element iron. The results showed the injection time is from 39-743 minutes, which corresponded to the energy range of particles. The coronal mass injection was detected at the end time of this flare that affects in increasing the injection time. This solar event didn’t affect the Earth’s magnetic field as the value of kp index is 4 at the end of solar flare. The value of kp index has increased to 8 on 7th September, 2017 due to another solar event occurred from same sunspot region.

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