AWSoM Magnetohydrodynamic Simulation of a Solar Active Region. II. Statistical Analysis of Alfvén Wave Dissipation and Reflection, Scaling Laws, and Energy Budget on Coronal Loops

Abstract

The coronal heating problem has been a major challenge in solar physics, and a tremendous amount of effort has been made over the past several decades to solve it. In this paper, we aim at answering how the physical processes behind the Alfvén wave turbulent heating adopted in the Alfvén Wave Solar atmosphere Model (AWSoM) unfold in individual plasma loops in an active region (AR). We perform comprehensive investigations in a statistical manner on the wave dissipation and reflection, temperature distribution, heating scaling laws, and energy balance along the loops, providing in-depth insights into the energy allocation in the lower solar atmosphere. We demonstrate that our 3D global model with a physics-based phenomenological formulation for the Alfvén wave turbulent heating yields a heating rate exponentially decreasing from loop footpoints to top, which had been empirically assumed in the past literature. A detailed differential emission measure (DEM) analysis of the AR is also performed, and the simulation compares favorably with DEM curves obtained from Hinode/Extreme-ultraviolet Imaging Spectrometer observations. This is the first work to examine the detailed AR energetics of our AWSoM model with high numerical resolution and further demonstrates the capabilities of low-frequency Alfvén wave turbulent heating in producing realistic plasma properties and energetics in an AR.

Adjusting the Potential Field Source Surface Height Based on Magnetohydrodynamic Simulations

“…and van der Holst et al (2014) described the physics within AWSoM in great detail, while van der Holst et al (2022) discussed the recent improvement of the Alfvén wave turbulence cascade. AWSoM results have shown reasonable agreement with in situ and remote observations under different solar wind conditions(Jin et al 2012;Oran et al 2013;Sachdeva et al 2019;Sachdeva et al 2021;Szente et al 2022;Huang et al 2023;Szente et al 2023;Shi et al 2024) and were widely used in the community(Jian et al 2016;Lloveras et al 2020;Henadhira Arachchige et al 2022).…”