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Title: Numerical simulations of Mach stem formation via intersecting bow shocks

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 g 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. In conclusion, our ultimate goal, which is part of an ongoing research effort, is to characterize the physical and observational conse- quences of bow shock intersections including the formation of Mach stems.
Authors:
ORCiD logo [1] ;  [1] ;  [2] ;  [3]
  1. Univ. of Rochester, Rochester, NY (United States)
  2. Rice Univ., Houston, TX (United States)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Report Number(s):
DOE-Rice-2037-7
Journal ID: ISSN 1574-1818; PII: S157418181500004X
Grant/Contract Number:
NA0002037; SC0001063
Type:
Accepted Manuscript
Journal Name:
High Energy Density Physics
Additional Journal Information:
Journal Volume: 17; Journal Issue: PA; Journal ID: ISSN 1574-1818
Publisher:
Elsevier
Research Org:
Rice Univ., Houston, TX (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; Shock wave phenomena Herbig-Haro objects; ISM; Mach stems; Jets and outflows
OSTI Identifier:
1462541
Alternate Identifier(s):
OSTI ID: 1252564

Hansen, E. C., Frank, A., Hartigan, P., and Yirak, K.. Numerical simulations of Mach stem formation via intersecting bow shocks. United States: N. p., Web. doi:10.1016/j.hedp.2014.12.005.
Hansen, E. C., Frank, A., Hartigan, P., & Yirak, K.. Numerical simulations of Mach stem formation via intersecting bow shocks. United States. doi:10.1016/j.hedp.2014.12.005.
Hansen, E. C., Frank, A., Hartigan, P., and Yirak, K.. 2015. "Numerical simulations of Mach stem formation via intersecting bow shocks". United States. doi:10.1016/j.hedp.2014.12.005. https://www.osti.gov/servlets/purl/1462541.
@article{osti_1462541,
title = {Numerical simulations of Mach stem formation via intersecting bow shocks},
author = {Hansen, E. C. and Frank, A. and Hartigan, P. and Yirak, K.},
abstractNote = {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 g 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. In conclusion, our ultimate goal, which is part of an ongoing research effort, is to characterize the physical and observational conse- quences of bow shock intersections including the formation of Mach stems.},
doi = {10.1016/j.hedp.2014.12.005},
journal = {High Energy Density Physics},
number = PA,
volume = 17,
place = {United States},
year = {2015},
month = {1}
}