Large Scale Earth’s Bow Shock with Northern IMF as Simulated by PIC Code in Parallel with MHD Model

Abstract

In this paper, we propose a 3D kinetic model (particle-in-cell, PIC) for the description of the large scale Earth’s bow shock. The proposed version is stable and does not require huge or extensive computer resources. Because PIC simulations work with scaled plasma and field parameters, we also propose to validate our code by comparing its results with the available MHD simulations under same scaled solar wind (SW) and (IMF) conditions. We report new results from the two models. In both codes the Earth’s bow shock position is found to be ≈14.8 R _E along the Sun–Earth line, and ≈29 R _E on the dusk side. Those findings are consistent with past in situ observations. Both simulations reproduce the theoretical jump conditions at the shock. However, the PIC code density and temperature distributions are inflated and slightly shifted sunward when compared to the MHD results. Kinetic electron motions and reflected ions upstream may cause this sunward shift. Species distributions in the foreshock region are depicted within the transition of the shock (measured ≈2 c/ω _pi for Θ _Bn = 90° and M _MS = 4.7) and in the downstream. The size of the foot jump in the magnetic field at the shock is measured to be (1.7c/ω _pi ). In the foreshocked region, the thermal velocity is found equal to 213 km s⁻¹ at 15R _E and is equal to 63 km s ⁻¹ at 12 R _E (magnetosheath region). Despite the large cell size of the current version of the PIC code, it is powerful to retain macrostructure of planets magnetospheres in very short time, thus it can be used for pedagogical test purposes. It is also likely complementary with MHD to deepen our understanding of the large scale magnetosphere.