Multi-directional investigations on quiet time suprathermal ions measured by ASPEX-STEPS on-board Aditya L1
Abstract
The origin, acceleration and anisotropy of suprathermal ions in the interplanetary medium during quiet periods have remained poorly understood issues in solar wind physics. To address these aspects, we derive the spectral indices for the quiet time suprathermal ions based on the measurements by the four directionally separated sensors that are part of the Supra-Thermal and Energetic Particle Spectrometer (STEPS) of Aditya Solar Wind Particle EXperiment (ASPEX) on-board Aditya L1 spacecraft. Three out of four STEPS sensors Parker Spiral (PS), Inter-Mediate (IM), Earth Pointing (EP) are in one plane (nearly aligned with the ecliptic plane) while the fourth sensor North Pointing (NP) is in a mutually orthogonal plane. The energy ranges covered by the PS, IM, EP and NP sensors are 0.36-1.32 MeV, 0.14-1.22 MeV, 0.39-1.33 MeV and 0.12-1.23 MeV respectively. The quiet intervals are identified during January November, 2024 and the derived spectral indices (differential directional flux versus energy) are found to be in the range of 2.0 for all directions in the time scale of a few days revealing isotropic nature of their distribution. Further analysis of elemental abundance ratios (3He/4He, Fe/O, and C/O) during the same quiet intervals obtained from the Ultra-Low Energy Isotope Spectrometer (ULEIS) on board the Advanced Composition Explorer (ACE) spacecraft suggests possible contributions from the leftover ions from the previous impulsive (Solar flares) and gradual events (CMEs) in the quiet time suprathermal ion pool.
Cite
@article{arxiv.2507.11952,
title = {Multi-directional investigations on quiet time suprathermal ions measured by ASPEX-STEPS on-board Aditya L1},
author = {Aakash Gupta and Dibyendu Chakrabarty and Santosh Vadawale and Aveek Sarkar and Bijoy Dalal and Shiv Kumar Goyal and Jacob Sebastian and P. Janardhan and Nandita Srivastava and M. Shanmugam and Neeraj Kumar Tiwari and Aaditya Sarda and Piyush Sharma and Anil Bhardwaj and Prashant Kumar and Manan S. Shah and Bhas Bapat and Pranav R. Adhyaru and Arpit R. Patel and Hitesh Kumar Adalja and Abhishek Kumar and Tinkal Ladiya and Sushil Kumar and Nishant Singh and Deepak Kumar Painkra and Abhishek J. Verma and Swaroop Banerjee and K. P. Subramanian and M. B. Dadhania},
journal= {arXiv preprint arXiv:2507.11952},
year = {2025}
}
Comments
15 pages, 11 figures, 1 table