Contact and pressure balance structures in two-fluid cosmic-ray hydrodynamics

1995 ◽  
Vol 442 ◽  
pp. 822 ◽  
Author(s):  
G. M. Webb ◽  
M. Brio ◽  
G. P. Zank ◽  
T. Story
Keyword(s):  
Cosmic Ray ◽  
Pressure Balance ◽  
Two Fluid

The time-asymptotic stability of shocks in cosmic-ray hydrodynamics

1988 ◽  
Vol 39 (3) ◽  
pp. 539-548 ◽  
Author(s):  
G. P. Zank
Keyword(s):  
Wave Equation ◽  
Asymptotic Stability ◽  
Short Wavelength ◽  
Cosmic Ray ◽  
Hydrodynamical Model ◽  
Shock Formation ◽  
Nonlinear Behaviour ◽  
Two Fluid

The nonlinear behaviour of short-wavelength perturbations in the two-fluid cosmic-ray hydrodynamical model is examined. We show that such a perturbation leads to shock formation and derive the appropriate wave equation. We show that a discontinuous perturbation incident on a weak cosmic-ray shock destabilizes, in a time-asymptotic sense, the shock.

The evolution of cosmic-ray-mediated magnetohydrodynamic shocks: A two-fluid approach

1994 ◽  
Vol 429 ◽  
pp. 748 ◽  
Author(s):  
Byung-Il Jun ◽  
David A. Clarke ◽  
Michael L. Norman
Keyword(s):  
Cosmic Ray ◽  
Two Fluid ◽  
Magnetohydrodynamic Shocks

Wave–wave interactions in two-fluid cosmic-ray hydrodynamics

1997 ◽  
Vol 57 (3) ◽  
pp. 631-676 ◽  
Author(s):  
G. M. WEBB ◽  
M. BRIO ◽  
G. P. ZANK ◽  
T. STORY
Keyword(s):  
Cosmic Ray ◽  
Wave Interactions ◽  
Two Fluid

scholarly journals Time-dependent simulation of oblique MHD cosmic-ray shocks using the two-fluid model

1995 ◽  
Vol 441 ◽  
pp. 629 ◽  
Author(s):  
Adam Frank ◽  
T. W. Jones ◽  
Dongsu Ryu
Keyword(s):  
Fluid Model ◽  
Cosmic Ray ◽  
Time Dependent ◽  
Two Fluid Model ◽  
Two Fluid

The interaction of long-wavelength compressive waves with a cosmic ray shock

1987 ◽  
Vol 37 (3) ◽  
pp. 363-372 ◽  
Author(s):  
G. P. Zank ◽  
J. F. Mckenzie
Keyword(s):  
Dispersion Equation ◽  
Transmission Coefficient ◽  
Cosmic Ray ◽  
Long Wavelength ◽  
The Stability ◽  
Two Fluid

This paper investigates the stability of a cosmic ray shock to long-wavelength perturbations. The problem is formulated in terms of finding the transmission coefficient for compressive waves across a cosmic ray shock by solving the generalized, two-fluid Rankine-Hugoniot relations. For strong shocks, the transmission coefficient confirms that compressive waves can undergo considerable amplification on passage through such shocks. The resonances of the transmission coefficient provides us with the dispersion equation governing the stability of the shock to long-wavelength ripple-like distortions. By using the principle of the argument method, it is established that cosmic ray shocks are stable.

scholarly journals Cosmic rays across the star-forming galaxy sequence – I. Cosmic ray pressures and calorimetry

2021 ◽  
Vol 502 (1) ◽  
pp. 1312-1333
Author(s):  
Roland M Crocker ◽  
Mark R Krumholz ◽  
Todd A Thompson
Keyword(s):  
Star Formation ◽  
Cosmic Rays ◽  
Surface Density ◽  
Large Scale ◽  
Gamma Ray ◽  
Formation Rate ◽  
Cosmic Ray ◽  
Gas Content ◽  
Critical Surface ◽  
Pressure Balance

ABSTRACT In the Milky Way (MW), cosmic rays (CRs) are dynamically important in the interstellar medium (ISM), contribute to hydrostatic balance, and may help regulate star formation. However, we know far less about the importance of CRs in galaxies whose gas content or star formation rate (SFR) differ significantly from those of the MW. Here, we construct self-consistent models for hadronic CR transport, losses, and contribution to pressure balance as a function of galaxy properties, covering a broad range of parameters from dwarfs to extreme starbursts. While the CR energy density increases from ∼1 eV cm−3 to ∼1 keV cm−3 over the range from sub-MW dwarfs to bright starbursts, strong hadronic losses render CRs increasingly unimportant dynamically as the SFR surface density increases. In MW-like systems, CR pressure is typically comparable to turbulent gas and magnetic pressure at the galactic mid-plane, but the ratio of CR to gas pressure drops to ∼10−3 in dense starbursts. Galaxies also become increasingly CR calorimetric and gamma-ray bright in this limit. The degree of calorimetry at fixed galaxy properties is sensitive to the assumed model for CR transport, and in particular to the time CRs spend interacting with neutral ISM, where they undergo strong streaming losses. We also find that in some regimes of parameter space hydrostatic equilibrium discs cannot exist, and in Paper II of this series we use this result to derive a critical surface in the plane of star formation surface density and gas surface density beyond which CRs may drive large-scale galactic winds.

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