A cosmic ray current driven instability in partially ionised media

Abstract

We investigate the growth of hydromagnetic waves driven by streaming cosmic rays in the precursor environment of a supernova remnant shock. It is known that transverse waves propagating parallel to the mean magnetic field are unstable to anisotropies in the cosmic ray distribution, and may provide a mechanism to substantially amplify the ambient magnetic field. We quantify the extent to which temperature and ionisation fractions modify this picture. Using a kinetic description of the plasma we derive the dispersion relation for a collisionless thermal plasma with a streaming cosmic ray current. Fluid equations are then used to discuss the effects of neutral-ion collisions. We calculate the extent to which the environment into which the cosmic rays propagate influences the growth of the magnetic field, and determines the range of possible growth rates. If the cosmic ray acceleration is efficient, we find that very large neutral fractions are required to stabilise the growth of the non-resonant mode. For typical supernova parameters in our galaxy, thermal effects do not significantly alter the growth rates. For weakly driven modes, ion-neutral damping can dominate over the instability at more modest ionisation fractions. In the case of a supernova shock interacting with a molecular clouds, such as in RX J1713.7-3946, with high density and low ionisation, the modes can be rapidly damped.

5 pages, 2 figures, accepted to A&A. Corrections made. Applications added

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Cited by in corpus (48)

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• Escape-limited Model of Cosmic-ray Acceleration Revisited
• Electron-Ion Temperature Equilibration in Collisionless Shocks: the Supernova Remnant-Solar Wind Connection
• The transport of cosmic rays in self-excited magnetic turbulence
• Fundamentals of collisionless shocks for astrophysical application, 2. Relativistic shocks
• Core-collapse model of broadband emission from SNR RX J1713.7-3946 with thermal X-rays and Gamma-rays from escaping cosmic rays
• On Fermi acceleration and MHD-instabilities at ultra-relativistic magnetized shock waves
• Two-Dimensional particle-in-cell simulations of the nonresonant, cosmic-ray driven instability in SNR shocks
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• High-Energy Neutrinos and Gamma-Rays from Non-Relativistic Shock-Powered Transients
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• Plasma instabilities as a result of charge exchange in the downstream region of supernova remnant shocks
• The Heating of Thermal Electrons in Fast Collisionless Shocks: The Integral Role of Cosmic Rays
• Novae as Tevatrons: Prospects for CTA and IceCube
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• Steady-State Solutions in Nonlinear Diffusive Shock Acceleration
• Magnetic fields in cosmic particle acceleration sources
• Electron-Ion Temperature Ratio in Astrophysical Shocks
• Understanding hadronic gamma-ray emission from supernova remnants
• Multiwavelength study of Cygnus A II. X-ray inverse-Compton emission from a relic counterjet and implications for jet duty-cycles
• Diffuse γ-ray emission from self-confined cosmic rays around Galactic sources
• Effects of Leakage Neutral Particles on Shocks
• Effects of Neutral Particles on Modified Shocks at Supernova Remnants
• Fermi~I particle acceleration in converging flows mediated by magnetic reconnection
• Magnetic field amplification by collisionless shocks in partially ionized plasmas
• Evidence for multiple shocks from the $\gamma$-ray emission of RS Ophiuchi
• Collisionless shocks in partly ionized plasma with cosmic rays: microphysics of non-thermal components
• Influence of Ion-Neutral Damping on the Cosmic-Ray Streaming Instability: Magnetohydrodynamic Particle-in-cell Simulations
• Reacceleration of electrons in supernova remnants
• Bell-Instability-Mediated Spectral Modulation of Hadronic Gamma Rays from a Supernova Remnant Interacting with a Molecular Cloud
• Particle acceleration and magnetic field amplification in massive young stellar object jets
• Plus Charge Prevalence in Cosmic Rays: Room for Dark Matter in the Positron Spectrum
• Environmental limits on the non-resonant cosmic-ray current-driven instability
• Spectra of accelerated particles at supernova shocks in the presence of neutral hydrogen: the case of Tycho
• Gamma-ray emission from spectrally resolved cosmic rays in galaxies
• Cosmic rays and molecular clouds
• Magnetic and density spikes in cosmic ray shock precursors
• $\gamma$-ray Emission from Classical Nova V392 Per: Measurements from Fermi and HAWC
• Cosmic-ray current-driven instabilities -- revisiting environmental conditions
• Enhancement of the non-resonant streaming instability by particle collisions
• Streaming cold cosmic ray back-reaction and thermal instabilities across the background magnetic field
• Interplay between the non-resonant streaming instability and self-generated pressure anisotropies
• Back-reaction instabilities of relativistic cosmic rays
• Time-dependent treatment of cosmic-ray spectral steepening due to turbulence driving