Electron Densities of Transition Region Loops Derived from IRIS O iv Spectral Data
| Autor: | Shiyu Liang, Ziyuan Wang, Zhenghua Huang, Hengyuan Wei, Hui Fu, Ming Xiong, Lidong Xia |
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| Jazyk: | angličtina |
| Rok vydání: | 2024 |
| Předmět: | |
| Zdroj: | The Astrophysical Journal Letters, Vol 966, Iss 1, p L6 (2024) |
| Druh dokumentu: | article |
| ISSN: | 2041-8213 2041-8205 |
| DOI: | 10.3847/2041-8213/ad3d5e |
| Popis: | 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 and 1401.2 Å ( ${T}_{\max }=1.4\times {10}^{5}$ 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 × 10 ^9 –3.5 × 10 ^11 cm ^−3 , 8–30 Mm, and 1.9 × 10 ^5 –1.3 × 10 ^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 ] ∝ ( L [Mm]) ^−0.78±0.42 , 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. |
| Databáze: | Directory of Open Access Journals |
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