Impact of solar wind depression on the dayside magnetosphere under northward interplanetary magnetic field

Abstract

Abstract. We present a follow up study of the sensitivity of the Earth's magnetosphere to solar wind activity using a particles-in-cell model (Baraka and Ben Jaffel, 2007), but here during northward Interplanetary Magnetic Field (IMF). The formation of the magnetospheric cavity and its elongation around the planet is obtained with the classical structure of a magnetosphere with parallel lobes. An impulsive disturbance is then applied to the system by changing the bulk velocity of the solar wind to simulate a decrease in the solar wind dynamic pressure followed by its recovery. In response to the imposed drop in the solar wind velocity, a gap (abrupt depression) in the incoming solar wind plasma appears moving toward the Earth. The gap's size is a ∼15 R E and is comparable to the sizes previously obtained for both B z < 0 and B z = 0. During the initial phase of the disturbance along the x-axis, the dayside magnetopause (MP) expands slower than the previous cases of IMF orientations as a result of the abrupt depression. The size of the MP expands nonlinearly due to strengthening of its outer boundary by the northward IMF. Also, during the initial 100 t, the MP shrank down from 13.3 R E to ∼9.2 R E before it started expanding, a phenomenon that was also observed for southern IMF conditions but not during the no IMF case. As soon as they felt the solar wind depression, cusps widened at high altitude while dragged in an upright position. For the field's topology, the reconnection between magnetospheric and magnetosheath fields is clearly observed in both the northward and southward cusps areas. Also, the tail region in the northward Correspondence to: S. Baraka (suleiman.baraka@gmail.com) IMF condition is more confined, in contrast to the fishtailshape obtained in the southward IMF case. An X-point is formed in the tail at ∼110 R E compared to ∼103 R E and ∼80 R E for B z = 0 and B z < 0, respectively. Our findings are consistent with existing reports from many space observatories (Cluster, Geotail, Themis, etc.) for which predictions are proposed to test furthermore our simulation technique.

Atmospheric Escape Processes and Planetary Atmospheric Evolution

“…An example of a code in development to address some of these problems could be Institut d'Astrophysique de Paris Particle‐In‐Cell‐ Electromagnetic Global 3D Code (IAPIC), a particle‐in‐cell electromagnetic 3‐D global code, used (Baraka, 2016; Baraka & Ben‐Jaffel, 2010; Ben‐Jaffel & Ballester, 2013, 2014) to produce the magnetosphere ( XZ plane) of an Earth‐like planet. Both plasma density and field lines are shown in Figure 12.…”

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

“…In this paper,a Particle-In-Cell PIC is used for the description of Earth's bow shock. The proposed version is stable and does not require huge or expensive computer resources since we are interested in the large scales of the system (1R E ) 5 . The scaled plasmas and fields parameters used in PIC, was also used to validate our code with available MHD simulations.…”

The impact of Radial and Non-Radial IMF on the Earth's Magnetopause Size, Shape, and Dawn-Dusk Asymmetry from Global 3D Kinetic Simulations.

“…for treating the plasma kinetically. IAPIC has previously been applied to simulate various magnetospheres in the solar system (S. Baraka & Ben-Jaffel, 2011;Ben-Jaffel & Ballester, 2013S. Baraka, 2016).…”