Foreshock compressive structure-magnetosheath jet coupling in a global hybrid-Vlasov simulation

Abstract

<p>Magnetosheath jets are a class of phenomena usually defined as pulses of high dynamic pressure in the magnetosheath, but the details of their origins are currently unclear. Many theories on the origin of magnetosheath jets have been developed, such as bow shock rippling and foreshock structures. The usefulness of spacecraft data in studying some of them is limited, due to the transient and localised nature of jets. We use the 5D global hybrid-Vlasov simulation Vlasiator in a statistical study to investigate the relationship between compressive structures in the foreshock and magnetosheath jets. Foreshock compressive structures and magnetosheath jets are identified and their evolution over time is tracked. We find that up to 75% of magnetosheath jets forming at the bow shock are associated with foreshock compressive structures impacting the bow shock at the same location. Furthermore, magnetosheath jets that are associated with foreshock compressive structures penetrate deeper into the magnetosheath than jets that are not associated with foreshock compressive structures.</p>