Modeling Realistic Heating Profiles of Transition Region Hot Loops on the Sun: Evidence for Impulsive Heating and Non-equilibrium Ionization

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Hauptverfasser: Bahauddin, Shah Mohammad, Bradshaw, Stephen J
Format: Preprint
Veröffentlicht: 2024
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author Bahauddin, Shah Mohammad
Bradshaw, Stephen J
author_facet Bahauddin, Shah Mohammad
Bradshaw, Stephen J
contents The study examines the heating profile of hot solar transition region loops, particularly focusing on transient brightenings observed in IRIS 1400Å slit-jaw images. The findings challenge the adequacy of simplistic, singular heating mechanisms, revealing that the heating is temporally impulsive and requires a spatially complex profile with multiple heating scales. A forward modeling code is utilized to generate synthetic IRIS emission spectra of these loops based on HYDRAD output, confirming that emitting ions are out of equilibrium. The modeling further indicates that density-dependent dielectronic recombination rates must be included to reproduce the observed line ratios. Collectively, this evidence substantiates that the loops are subject to impulsive heating and that the components of the transiently brightened plasma are driven far from thermal equilibrium. Heating events such as these are ubiquitous in the transition region and the analysis described above provides a robust observational diagnostic tool for characterizing the plasma.
format Preprint
id arxiv_https___arxiv_org_abs_2405_08648
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Modeling Realistic Heating Profiles of Transition Region Hot Loops on the Sun: Evidence for Impulsive Heating and Non-equilibrium Ionization
Bahauddin, Shah Mohammad
Bradshaw, Stephen J
Solar and Stellar Astrophysics
Space Physics
The study examines the heating profile of hot solar transition region loops, particularly focusing on transient brightenings observed in IRIS 1400Å slit-jaw images. The findings challenge the adequacy of simplistic, singular heating mechanisms, revealing that the heating is temporally impulsive and requires a spatially complex profile with multiple heating scales. A forward modeling code is utilized to generate synthetic IRIS emission spectra of these loops based on HYDRAD output, confirming that emitting ions are out of equilibrium. The modeling further indicates that density-dependent dielectronic recombination rates must be included to reproduce the observed line ratios. Collectively, this evidence substantiates that the loops are subject to impulsive heating and that the components of the transiently brightened plasma are driven far from thermal equilibrium. Heating events such as these are ubiquitous in the transition region and the analysis described above provides a robust observational diagnostic tool for characterizing the plasma.
title Modeling Realistic Heating Profiles of Transition Region Hot Loops on the Sun: Evidence for Impulsive Heating and Non-equilibrium Ionization
topic Solar and Stellar Astrophysics
Space Physics
url https://arxiv.org/abs/2405.08648