Hybrid Simulations of the Cusp and Dayside Magnetosheath Dynamics Under Quasi-Radial Interplanetary Magnetic Fields

J Ng; L-J Chen; Y Omelchenko; Y Zou; B Lavraud

doi:10.1029/2022JA030359

Hybrid Simulations of the Cusp and Dayside Magnetosheath Dynamics Under Quasi-Radial Interplanetary Magnetic Fields

J Geophys Res Space Phys. 2022 Oct;127(10):e2022JA030359. doi: 10.1029/2022JA030359. Epub 2022 Oct 19.

Authors

J Ng^{1

2}, L-J Chen², Y Omelchenko^{3

4}, Y Zou⁵, B Lavraud⁶

Affiliations

¹ Department of Astronomy University of Maryland College Park MD USA.
² NASA Goddard Space Flight Center Greenbelt MD USA.
³ Trinum Research Inc San Diego CA USA.
⁴ Space Science Institute Boulder CO USA.
⁵ Department of Space Science University of Alabama in Huntsville Huntsville AL USA.
⁶ Laboratoire d'astrophysique de Bordeaux CNRS University Bordeaux Pessac France.

Abstract

Under quasi-radial interplanetary magnetic fields (IMF), foreshock turbulence can have an impact on the magnetosheath and cusps depending on the location of the quasi-parallel shock. We perform three-dimensional simulations of Earth's dayside magnetosphere using the hybrid code HYPERS, and compare northward and southward quasi-radial IMF configurations. We study the magnetic field configuration, fluctuations in the magnetosheath and the plasma in the regions around the northern cusp. Under northward IMF with Earthward B _x , there is a time-varying plasma depletion layer immediately outside the northern cusp. In the southward IMF case, the impact of foreshock turbulence and high-speed jets, together with magnetopause reconnection, can lead to strong density enhancements in the cusp.

Keywords: cusp; hybrid simulations; magnetosheath; quasi‐parallel shock.