AUTHOR=Tinoco-Arenas Arturo , Kajdič Primož , Preisser Luis , Blanco-Cano Xóchitl , Trotta Domenico , Burgess David 

TITLE=Parametric Study of Magnetosheath Jets in 2D Local Hybrid Simulations

JOURNAL=Frontiers in Astronomy and Space Sciences

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/astronomy-and-space-sciences/articles/10.3389/fspas.2022.793195

DOI=10.3389/fspas.2022.793195

ISSN=2296-987X

ABSTRACT=We perform 2D local hybrid simulations of collisionless shocks in order to study the properties of simulated magnetosheath jets as a function of shock properties, namely their Alfvénic Mach number (MA) and geometry (angle between the upstream magnetic field and the shock normal, Theta_BN). In total we perform 15 simulations with inflow speeds of Vin=3.3 VA (Alfvén velocity), 4.5 VA and 5.5 VA and Theta_BN= 15deg, 30deg, 45deg, 50deg\ and 65deg. Under these conditions, the shock MA varied between 4.28 and 7.42. In order to identify magnetosheath jets in the simulation outputs, we use four different criteria, equivalent to those utilized to identify subsets of magnetosheath jets, called high-speed jets (Plaschke et al. 2013), transient flux enhancements (Nemecek et al. 1998), density plasmoids (Karlsson et al. 2012;2015) and high-speed plasmoids . In our simulations, the density plasmoids were produced only by shocks with M_A>=5.7, while the high-speed plasmoids only formed downstream of shocks with MA>=6.97. We show that higher MA shocks tend to produce faster jets that tend to have larger surface area, mass, linear momentum and kinetic energy, while these quantities tend to be anticorrelated with Theta_BN. In general, the increase of Theta_BN\ to up to 45deg\ results in increased jet formation rates. In the case of high-speed jets in runs with Vin=3.3 VA and high-speed plasmoids, the jet formation anticorrelates with Theta_BN. The jet production all but ceases for Theta_BN =65deg regardless of the shock's MA. The maximum distances of the magnetosheath jets from the shocks were <~140 di (upstream ion inertial lengths), which, estimating 1 di~100-150 km at Earth, corresponds to 2.4-3.3 Earth radii. Thus, none of the simulated jets reached distances equivalent to the average extension of the Earth's subsolar magnetosheath, which would make them the equivalents of geoeffective jets. Higher MA\ shocks are probably needed in order to produce such jets.