Electron densities of Transition Region Loops derived from IRIS O IV spectral data

Fuente: arXiv
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Autori principali: Liang, Shiyu, Wang, Ziyuan, Huang, Zhenghua, Wei, Hengyuan, Fu, Hui, Xiong, Ming, Xia, Lidong
Natura: Preprint
Pubblicazione: 2024
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author Liang, Shiyu
Wang, Ziyuan
Huang, Zhenghua
Wei, Hengyuan
Fu, Hui
Xiong, Ming
Xia, Lidong
author_facet Liang, Shiyu
Wang, Ziyuan
Huang, Zhenghua
Wei, Hengyuan
Fu, Hui
Xiong, Ming
Xia, Lidong
contents Loops are fundamental structures in the magnetized atmosphere of the sun. Their physical properties are crucial for understanding the nature of the solar atmosphere. Transition region loops are relatively dynamic and their physical properties have not yet been fully understood. With spectral data of the line pair of O IV 1399.8 Å& 1401.2 Å($T_{max}=1.4\times10^5$ K) of 23 transition region loops obtained by IRIS, we carry out the first systematic analyses to their loop lengths ($L$), electron densities ($n_e$) and effective temperatures. We found electron densities, loop lengths and effective temperatures of these loops are in the ranges of $8.9\times10^{9}$-$3.5\times10^{11}$ cm$^{-3}$, 8-30 Mm and $1.9\times10^5$-$1.3\times10^6$ K, respectively. At a significant level of 90\%, regression analyses show that the relationship between electron densities and loop lengths is $n_e[cm^{-3}]\varpropto (L[Mm])^{-0.78\pm0.42}$, while the dependences of electron densities on effective temperatures and that on the line intensities are not obvious. These observations demonstrate that transition region loops are significantly different than their coronal counterparts. Further studies on the theoretical aspect based on the physical parameters obtained here are of significance for understanding the nature of transition region loops.
format Preprint
id arxiv_https___arxiv_org_abs_2404_09805
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Electron densities of Transition Region Loops derived from IRIS O IV spectral data
Liang, Shiyu
Wang, Ziyuan
Huang, Zhenghua
Wei, Hengyuan
Fu, Hui
Xiong, Ming
Xia, Lidong
Solar and Stellar Astrophysics
Loops are fundamental structures in the magnetized atmosphere of the sun. Their physical properties are crucial for understanding the nature of the solar atmosphere. Transition region loops are relatively dynamic and their physical properties have not yet been fully understood. With spectral data of the line pair of O IV 1399.8 Å& 1401.2 Å($T_{max}=1.4\times10^5$ K) of 23 transition region loops obtained by IRIS, we carry out the first systematic analyses to their loop lengths ($L$), electron densities ($n_e$) and effective temperatures. We found electron densities, loop lengths and effective temperatures of these loops are in the ranges of $8.9\times10^{9}$-$3.5\times10^{11}$ cm$^{-3}$, 8-30 Mm and $1.9\times10^5$-$1.3\times10^6$ K, respectively. At a significant level of 90\%, regression analyses show that the relationship between electron densities and loop lengths is $n_e[cm^{-3}]\varpropto (L[Mm])^{-0.78\pm0.42}$, while the dependences of electron densities on effective temperatures and that on the line intensities are not obvious. These observations demonstrate that transition region loops are significantly different than their coronal counterparts. Further studies on the theoretical aspect based on the physical parameters obtained here are of significance for understanding the nature of transition region loops.
title Electron densities of Transition Region Loops derived from IRIS O IV spectral data
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2404.09805