Citation

BibTex format

@article{Cuesta:2024:1538-4357/ad68fd,
author = {Cuesta, ME and Cummings, AT and Livadiotis, G and McComas, DJ and Cohen, CMS and Khoo, LY and Sharma, T and Shen, MM and Bandyopadhyay, R and Rankin, JS and Szalay, JR and Farooki, HA and Xu, Z and Muro, GD and Stevens, ML and Bale, SD},
doi = {1538-4357/ad68fd},
journal = {Astrophysical Journal},
title = {Observations of Kappa Distributions in Solar Energetic Protons and Derived Thermodynamic Properties},
url = {http://dx.doi.org/10.3847/1538-4357/ad68fd},
volume = {973},
year = {2024}
}

RIS format (EndNote, RefMan)

TY  - JOUR
AB - In this paper, we model the high-energy tail of observed solar energetic proton energy distributions with a kappa distribution function. We employ a technique for deriving the thermodynamic parameters of solar energetic proton populations measured by the Parker Solar Probe Integrated Science Investigation of the Sun EPI-Hi high-energy telescope, over energies from 10 to 60 MeV. With this technique, we explore, for the first time, the characteristic thermodynamic properties of the solar energetic protons associated with an interplanetary coronal mass ejection (ICME) and its driven shock. We find that: (1) the spectral index or, equivalently, the thermodynamic parameter kappa of solar energetic protons (κ EP) gradually increases, starting from the pre-ICME region (upstream of the CME-driven shock), reaching a maximum in the CME ejecta (κ EP ≈ 3.5), followed by a gradual decrease throughout the trailing portion of the CME; (2) the solar energetic proton temperature and density (T EP and n EP) appear anticorrelated, a behavior consistent with subisothermal polytropic processes; and (3) values of T EP and κ EP appear to be positively correlated, indicating an increasing entropy with time. Therefore, these proton populations are characterized by a complex and evolving thermodynamic behavior, consisting of multiple subisothermal polytropic processes, and a large-scale trend of increasing temperature, kappa, and entropy. This study and its companion study by Livadiotis et al. open up a new set of procedures for investigating the thermodynamic behavior of energetic particles and their shared thermal properties.
AU - Cuesta,ME
AU - Cummings,AT
AU - Livadiotis,G
AU - McComas,DJ
AU - Cohen,CMS
AU - Khoo,LY
AU - Sharma,T
AU - Shen,MM
AU - Bandyopadhyay,R
AU - Rankin,JS
AU - Szalay,JR
AU - Farooki,HA
AU - Xu,Z
AU - Muro,GD
AU - Stevens,ML
AU - Bale,SD
DO - 1538-4357/ad68fd
PY - 2024///
SN - 0004-637X
TI - Observations of Kappa Distributions in Solar Energetic Protons and Derived Thermodynamic Properties
T2 - Astrophysical Journal
UR - http://dx.doi.org/10.3847/1538-4357/ad68fd
VL - 973
ER -