Cusp dynamics under northward IMF using three‐dimensional global particle‐in‐cell simulations

Abstract

The interaction of the solar wind with the terrestrial magnetosphere is analyzed with the help of three‐dimensional (3‐D) global, full‐electromagnetic particle‐in‐cell (PIC) simulations, in the configuration where the interplanetary magnetic field (IMF) is steadily northward. The present study is mainly focused on the cusp region and associated particle momenta dynamics. Within the present context and to the best of our knowledge, this work represents the first numerical simulation for analyzing the cusp dynamics using a fully self‐consistent 3‐D kinetic and electromagnetic approach. The main goals of the study are the following: (i) to retrieve the main known features of the cusp to validate the use of 3‐D PIC “global” simulations, (ii) to compare with previous results obtained with 3‐D MHD simulations, (iii) to create an updated global view of the cusp based on use of 3‐D PIC simulation, which cannot be obtained from a MHD approach, and (iv) to compare with statistical results from the Cluster mission. In particular, the stagnant exterior cusp (SEC) identified in previous statistical analysis of experimental data is retrieved, and it is possible to more precisely define the edges of the SEC region. In addition, we will focus on cusp features recently observed by the Cluster mission, for example, the Alfvén Transition Layer or ATL and on the features not reproduced by either MHD or the hybrid approach, which have been used to characterize the outer edges of the cusp more clearly.

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

“…The plasma inertia effects is considered in our PIC simulation, as a consequence the length of the simulation box is very much larger than the Debye length λ Dei =(0.11, 0.11), the gyro-radius ρ ce,i =(1. 25,20) and the inertia lengths c ωpe,i = (5, 80)for electrons and ions respectively.…”

Numerical study of penetration and distribution of charged particles in the magnetosphere during southward IMF case

“…We used the updated version of the 3D Stanford PIC code (Tristan code) for our simulation 11–14 . For this research, we used the simulation similar to the previous work 15 .…”

“…We used the updated version of the 3D Stanford PIC code (Tristan code) for our simulation. [11][12][13][14] For this research, we used the simulation similar to the previous work. 15 The numerical study includes three-dimensional electromagnetic full-particle global simulation model with the time sequence of the IMF rotations as follows: phase (i), from time step 0 to 1,500, there is no IMF and the magnetosphere is generated using a magnetic dipole field; phase (ii), a Northward IMF (Bz = 0.215) is gradually turned on from 1,501 to 1,800.…”

“…Since then, many studies including cusp's dynamics and particle precipitations have been done. The cusp is defined as a region of high‐density plasma, highly turbulent and depressed magnetic field, and stagnant flow 10–12 …”

“…The cusp is defined as a region of high-density plasma, highly turbulent and depressed magnetic field, and stagnant flow. [10][11][12] The aim of the present simulation study is to investigate the dependence of the energetic charged particles penetration upon solar wind velocity using the updated version of the 3D Stanford PIC code. The specific goals of this study are to estimate the percentage of penetration of the energetic charged particles including electrons and ions in four regions: cusp, plasmasphere, sunward, and tailward reconnection sites.…”