The Parker Instability with Cosmic Ray Streaming

Abstract

Recent studies have found that cosmic ray transport plays an important role in feedback processes such as star formation and the launching of galactic winds. Although cosmic ray buoyancy is widely held to be a destabilizing force in galactic disks, the effect of cosmic ray transport on the stability of stratified systems has yet to be analyzed. We perform a stability analysis of a stratified layer for three different cosmic ray transport models: decoupled (Classic Parker), coupled with ${\gamma }_c=4/3$ but not streaming (Modified Parker), and finally coupled with streaming at the Alfvén speed. When the compressibility of the cosmic rays is decreased the system becomes much more stable, but the addition of cosmic ray streaming to the Parker Instability severely destabilizes it. Through comparison of these three cases and analysis of the work contributions for the perturbed quantities of each system, we demonstrate that cosmic ray heating of the gas is responsible for the destabilization of the system. We find that a 3D system is unstable over a larger range of wavelengths than the 2D system. Therefore, the Parker Instability with cosmic ray streaming may play an important role in cosmic ray feedback.

arXiv comment13 pages, 6 figures, 1 table, Accepted to ApJ

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Cited by in corpus (16)

• Simulations of cosmic ray propagation
• Thermal Instability of Halo Gas Heated by Streaming Cosmic Rays
• Cosmic Ray Driven Outflows from the Large Magellanic Cloud: Contributions to the LMC Filament
• The Role of the Parker Instability in Structuring the Interstellar Medium
• Implementation of CR Energy SPectrum (CRESP) algorithm in PIERNIK MHD code. I. Spectrally resolved propagation of CR electrons on Eulerian grids
• Cosmic rays across the star-forming galaxy sequence. I: Cosmic ray pressures and calorimetry
• The Launching of Cosmic Ray Driven Outflows
• Dynamics of the Parker-Jeans instability of gaseous disks including the effect of cosmic rays
• The Cosmic Ray Staircase: the Outcome of the Cosmic Ray Acoustic Instability
• Stress-Testing Cosmic Ray Physics: The Impact of Cosmic Rays on the Surviving Disk of Ram Pressure Stripped Galaxies
• A Dynamical Study of Extraplanar Diffuse Ionized Gas in NGC 5775
• Steady states of the Parker instability
• Outflows in the presence of cosmic rays and waves with cooling
• Outflows in the presence of cosmic rays and waves
• The Impact of Cosmic Ray Injection on Magnetic Flux Tubes in a Galactic Disk
• Revisiting the Equipartition Assumption in Star-forming Galaxies