3D study of the impact of the Radial IMF on the Earth's Magnetopause size and shape and the dawn-dusk asymmetry. IAPPIC 3D Simulations

While the impact of southward and northward IMF on the dynamics of Earth's magnetosphere have been extensively covered in the last 4 decades, only recently has attention been focused on radially directed IMF. Using global three-dimensional kinetic simulation, we investigate the impact of radial IMF on the general macrostructure of Earth's Magnetosphere. Purely radial (Bx only) IMF was considered in this study. The solar wind in our simulation is not aligned with Parker spiral pattern, and we considered a dipole tilt of 31^o . It was found that the Magnetopause expanded to 12.8 R_E along magnetic equator if compared to 10 R_E typical case, and around 14 R_E along sun-earth line projection. It was found that the foot of the shocked solar wind experienced a factor of 2 density increase relative to solar wind input value, and this may be caused by one of the components of the induced magnetic force close to the Magnetopause. The magnetic force (V x B ) for radial IMF is zero, until it hits the Magnetopause. It was shown that the induced magnetic force along 0X axis and directed sunward is a dragging force for plasma, which made the Magnetopause expands while (v x B)_y contribute to the dawn-dusk asymmetry. Finally, we examined the (E x B) drifts, and found that the Y-component of this drift started as early as the bow shock position. These asymmetries inside the magnetosphere and/or magnetosheath impact the solar wind magnetosphere coupling. The new version of IAPPIC includes spatial resolution of 0.1 R_E, a planet tilt 31^o and ion to electron mass ratio of 64.