[P-EM14] Frontiers in solar physics

[PEM14-P09] Verification of the inversion method for electric field and velocity on the photosphere

*Masahiro Nobata¹, Takafumi Kaneko^2,3, Kanya Kusano¹ (1.Institute for Space-Earth Environmental Research, Nagoya University, 2.Lockheed Martin Solar and Astrophysics Laboratory, 3.High Altitude Observatory/National Center for Atmospheric Research)

Keywords:the Sun, magnetic field, simulation, inverse problem

To understand the mechanism of solar flares and coronal activity, it is necessary to investigate the three-dimensional structure of the solar coronal magnetic field. However, since the coronal magnetic field cannot be observed directly, a data-driven MHD simulation that numerically reproduces the coronal magnetic field from the observation data of the photospheric magnetic field has recently been developed. To conduct a data-driven simulation, we must determine the electric and velocity fields on the photosphere as boundary conditions. Several methods have recently been developed to do this. For instance, Fisher et al. (2010) developed a method for this purpose, exploiting the vector magnetic field's poloidal-toroidal decomposition (PTD). Kaneko et al. (2021) used this method to simulate observed mesoscale flares successfully. However, it has not been quantitatively investigated how accurately the PTD reproduces the electric and velocity fields and the dependencies of the PTD on the observation parameters. The objective of this study is to quantitatively evaluate the reproducibility of the electric field and velocity field by PTD. Therefore, we used the Spaceweather HMI Active Region Patch (SHARP) data observed by the Helioseismic and Magnetic Imager (HMI) onboard Solar Dynamics Observatory (SDO) satellite. We used the SHARP of the active region NOAA 11302 and produced the two vector magnetograms by uniformly shifting the SHARP data in a certain spatial direction. The two magnetograms correspond to sequential data in which the magnetic field is uniformly advected for a constant time at a certain velocity. Therefore, the reproducibility can be evaluated quantitatively by comparing the velocities and electric fields reproduced from the two magnetograms with the advective velocities and the corresponding electric fields. As a result, we found that the reproduction of the electric field is relatively good in the strong magnetic field region, while the electric field is hardly reproduced in the region where the magnetic field is weaker than 1000G. It was also found that the reproduced electric field tends to be smaller than the true value, even in the strong magnetic field region. In addition, we will investigate the dependency of the reproducibility on the time interval and spatial structure of the observed magnetic field. We also report on the reproduction experiment using the MHD simulations of the emerging flux.