Construction of coronal hole and active region magnetohydrostatic solutions in two dimensions: Force and energy balance

Terradas, J., Soler, R., Oliver, R., Antolin, Patrick, Arregui, I., Luna, M., Piantschitsch, I., Soubrié, E. and Ballester, J. L. (2022) Construction of coronal hole and active region magnetohydrostatic solutions in two dimensions: Force and energy balance. Astronomy & Astrophysics, 660. A136. ISSN 0004-6361

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Coronal holes and active regions are typical magnetic structures found in the solar atmosphere. We propose several magnetohydrostatic equilibrium solutions that are representative of these structures in two dimensions. Our models include the effect of a finite plasma-β and gravity, but the distinctive feature is that we incorporate a thermal structure with properties similar to those reported by observations. We developed a semi-analytical method to compute the equilibrium configuration. Using this method, we obtain cold and under-dense plasma structures in open magnetic fields representing coronal holes, while in closed magnetic configurations, we achieve the characteristic hot and over-dense plasma arrangements of active regions. Although coronal holes and active regions seem to be antagonistic structures, we find that they can be described using a common thermal structure that depends on the flux function. In addition to the force balance, the energy balance is included in the constructed models using an a posteriori approach. From the two-dimensional computation of thermal conduction and radiative losses in our models, we infer the required heating function to achieve energy equilibrium. We find that the temperature dependence on height is an important parameter that may prevent the system from accomplishing thermal balance at certain spatial locations. The implications of these results are discussed in detail.

Item Type: Article
Additional Information: Funding information: This publication is part of the R+D+i project PID2020112791GB-I00, financed by MCIN/AEI/10.13039/501100011033. M.L. acknowledges support through the Ramón y Cajal fellowship RYC2018026129-I from the Spanish Ministry of Science and Innovation, the Spanish National Research Agency (Agencia Estatal de Investigación), the European Social Fund through Operational Program FSE 2014 of Employment, Education and Training and the Universitat de les Illes Balears. I.A. was supported by project PGC2018-102108-B I00 from Ministerio de Ciencia, Innovación y Universidades and FEDER funds. P.A. acknowledges funding from his STFC Ernest Rutherford Fellowship (No. ST/R004285/2). This research was funded in part by the Austrian Science Fund (FWF): J4624-N.
Uncontrolled Keywords: magnetohydrodynaics (MHD), Sun: magnetic fields
Subjects: F800 Physical and Terrestrial Geographical and Environmental Sciences
F900 Others in Physical Sciences
Department: Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User: Rachel Branson
Date Deposited: 17 May 2022 10:02
Last Modified: 17 May 2022 10:15

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