[P-EM10] Dynamics of Magnetosphere and Ionosphere

[PEM10-08] Reconstruction of the diffusion region of magnetic reconnection with electron inertia and compressibility effects

*長谷川 洋¹、中村 琢磨²、Denton Richard³ (1.宇宙航空研究開発機構宇宙科学研究所、2.グラーツ大学、3.ダートマス大学)

キーワード：磁気リコネクション、磁気圏尾部、電子拡散領域

A method based on electron magnetohydrodynamics (EMHD) for the reconstruction of steady, two-dimensional plasma and magnetic field structures from data taken by a single spacecraft, first developed by Sonnerup et al. (2016), is extended to include several new effects. These are inhomogeneity of the electron density and temperature, electron inertia effects, and a guide magnetic field in and around the electron diffusion region (EDR), which is the central part of the magnetic reconnection region. The new method assumes that the electron density and temperature are constant along, but may vary across, the magnetic field lines. We present two models for the reconstruction of electron streamlines. The first model is not constrained by any specific formula for the electron pressure tensor term in the generalized Ohm’s law that is responsible for electron demagnetization in the EDR, and the other is a modification of the original model to include the inertia and compressibility effects. Benchmark tests using data from fully kinetic simulations show that our new method is applicable to both antiparallel and guide-field (component) reconnection, and the electron velocity field can be better reconstructed by including the inertia effects. The new EMHD reconstruction technique has been applied to an EDR of magnetotail reconnection encountered by the Magnetospheric Multiscale spacecraft on 11 July 2017, reported by Torbert et al. (2018) and reconstructed with the original inertia-less model by Hasegawa et al. (2019). We demonstrate that the new method performs better in recovering the electric field and electron streamlines than the original version.