Abstract Details


Name: Bijoy Dalal
Affiliation: Physical Research Laboratory
Conference ID: TVS202510248
Title: Strong particle acceleration in CME events as observed by ASPEX-STEPS on board Aditya-L1
Authors and Co-Authors: Dibyendu Chakrabarty, Santosh Vadawale, Shiv Kumar Goyal , Jacob Sebastian, Aakash Gupta, M. Shanmugam
Abstract Type: Contributory Presentation
Abstract: Solar energetic particles (SEPs, ions with energies from 100s of keVs to 100s of MeVs, sometimes up to several GeVs) pose great threat to technologies and human resources in space. There are primarily two types of SEPs – (i) impulsive SEPs (ISEPs) originated from solar flares and (ii) gradual SEPs (GSEPs) accelerated by interplanetary shocks driven by coronal mass ejections (CMEs) and their interplanetary counterparts i.e. ICMEs. Because of larger fluence (flux integrated over time) and longer duration of gradual events, GSEPs are considered more harmful. It is believed that shock acceleration (diffusive shock acceleration and shock drift acceleration) is the primary cause for the generation of GSEPs. Both these acceleration mechanisms predict power law distribution of accelerated particle spectra up to very high energies. However, the observed GSEP spectra fall off very rapidly after a critical energy value. Therefore, there is lack of clarity about the exact mechanism responsible for GSEP energization. The SupraThermal and Energetic Particle Spectrometer (STEPS) of the Aditya Solar wind Particle EXperiment (ASPEX) payload on board the Aditya-L1 spacecraft has been designed to observe suprathermal particles and SEPs from multiple directions. During the last one and half years, ASPEX-STEPS has observed a number of SEP events, spectra of most of which are typical. However, on some occasions, ASPEX-STEPS has observed remarkably different particle spectra, which suggest strong acceleration of SEPs. Insights from these observations will be discussed.