Numerical simulations of Mach stem formation via intersecting bow shocks

作者：Hansen E C^*; Frank A; Hartigan P; Yirak K

来源：High Energy Density Physics, 2015, 17: 135-139.

DOI：10.1016/j.hedp.2014.12.005

• Shock wave phenomena
• Herbig-Haro objects
• ISM
• Mach stems
• Jets and outflows

Hubble Space Telescope observations show bright knots of Ha emission within outflowing young stellar jets. Velocity variations in the flow create secondary bow shocks that may intersect and lead to enhanced emission. When the bow shocks intersect at or above a certain critical angle, a planar shock called a Mach stem is formed. These shocks could produce brighter Ha emission since the incoming flow to the Mach stem is parallel to the shock normal. In this paper we report first results of a study using 2-D numerical simulations designed to explore Mach stem formation at the intersection of bow shocks formed by hypersonic "bullets" or "clumps". Our 2-D simulations show how the bow shock shapes and intersection angles change as the adiabatic index gamma changes. We show that the formation or lack of a Mach stem in our simulations is consistent with the steady-state Mach stem formation theory. Our ultimate goal, which is part of an ongoing research effort, is to characterize the physical and observational consequences of bow shock intersections including the formation of Mach stems.

• 出版日期2015-12
• 单位Los Alamos