[P-EM14] Frontiers in solar physics

[PEM14-P01] Finite Plasma β Three-dimensional Magnetic Field Extrapolation Based on MHD Relaxation Method

*山崎 大輝¹、三好 隆博²、井上 諭³ (1.国立研究開発法人宇宙航空研究開発機構宇宙科学研究所、2.広島大学大学院先進理工系科学研究科、3.ニュージャージー工科大学太陽地球環境研究センター)

キーワード：磁気流体力学、コロナ磁場、数値モデリング

Three-dimensional (3D) magnetic field in the solar atmosphere provides crucial information to understand the explosive phenomenon such as solar flares and coronal mass ejections. It is still hard that we determine the 3D magnetic field from direct observation, and nonlinear force-free field (NLFFF) extrapolation is one of the best modeling methods that provides 3D magnetic field. However, the method is based on zero-β assumption, i.e., the model ignores the gas pressure gradient and gravitational force. The magnetic field based on NLFFF is not well reconstructed in high-β region, such as in chromospheric or lower height layer and in weak field region. To overcome this problem, we need to consider the magnetohydrostatic equilibrium. In this study, we developed a finite plasma β magnetic field extrapolation method based on magnetohydrodynamic relaxation method. In our method, we consider a force balance of the Lorentz force and the gas pressure. We tested three different schemes and extrapolated 3D magnetic field using an observational photospheric vector magnetic field of solar active region NOAA 12887. The verification of three schemes is performed by comparing the residual force, and we concluded that our methods reduce ~4% of residual force of previous NLFFF.