[P-EM11] Frontiers in solar physics

[PEM11-P13] Magnetohydrostatic Three-dimensional Coronal Magnetic Field Extrapolation Based on MHD Relaxation Method

*山崎 大輝¹、井上 諭²、三好 隆博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.ニュージャージー工科大学太陽地球科学センター、3.広島大学大学院先進理工系科学研究科)

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 (MHS) equilibrium. In recent years, several methods that allow us to extrapolate coronal magnetic field based on MHS equation have been developed. In this study, we developed an MHS magnetic field extrapolation method, which can be applied to the observational data, based on magnetohydrodynamic relaxation method. In our method, we consider a force balance among the Lorentz force, the gas pressure, and the gravitational force. We tested our developed code by extrapolating 3D magnetic field using an observational photospheric vector magnetic field of solar active region (AR) NOAA 12887, which is well-studied AR by NLFFF. By comparing the extrapolated magnetic field configuration of NLFFF and that of MHS, we found that the magnetic twist is much more concentrated in low height region in the case of MHS comparing to NLFFF. In our presentation, we also discuss the defference of the residual force, magnetic twist distribution, and the magnetic free energy profile between NLFFF and MHS.