Kelvin-Helmholtz Instability in a Weakly Ionized Medium

Abstract

Ambient interstellar material may become entrained in outflows from massive stars as a result of shear flow instabilities. We study the linear theory of the Kelvin - Helmholtz instability, the simplest example of shear flow instability, in a partially ionized medium. We model the interaction as a two fluid system (charged and neutral) in a planar geometry. Our principal result is that for much of the relevant parameter space, neutrals and ions are sufficiently decoupled that the neutrals are unstable while the ions are held in place by the magnetic field. Thus, we predict that there should be a detectably narrower line profile in ionized species tracing the outflow compared with neutral species since ionized species are not participating in the turbulent interface with the ambient ISM. Since the magnetic field is frozen to the plasma, it is not tangled by the turbulence in the boundary layer.

21 pages, 4 figures

References in corpus (4)

• Magnetic Field Diagnostics Based on Far-Infrared Polarimetry: Tests Using Numerical Simulations
• Theoretical Models of Polarized Dust Emission from Protostellar Cores
• The MHD Kelvin-Helmholtz Instability: A Two-Dimensional Numerical Study
• The MHD Kelvin-Helmholtz Instability II: The Roles of Weak and Oblique Fields in Planar Flows

Cited by in corpus (18)

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• Two-dimensional simulations of coronal rain dynamics. I. Model with vertical magnetic field and an unbounded atmosphere
• The Kelvin-Helmholtz instability in weakly ionised plasmas: Ambipolar dominated and Hall dominated flows
• Jets and Wide Angle Outflows in Cepheus E: New Evidence from Spitzer
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• Small-scale solar jet formation and their associated waves and instabilities
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• Simulations of the Biermann battery mechanism in two-fluid partially ionised plasmas
• Turbulent entrainment origin of protostellar outflows
• Charged grains and Kelvin Helmholtz instability in molecular clouds
• An asymptotic model for the Kelvin-Helmholtz and Miles mechanisms of water wave generation by wind
• Normal mode analysis of fluid discontinuities: numerical method and application to magnetohydrodynamics