Collisionless conduction in a high-beta plasma: a collision operator for whistler turbulence
arXiv:2405.06481 · doi:10.1017/S002237782400151X
Abstract
The regulation of electron heat transport in high-beta, weakly collisional, magnetized plasma is investigated. A temperature gradient oriented along a mean magnetic field can induce a kinetic heat-flux-driven whistler instability (HWI), which back-reacts on the transport by scattering electrons and impeding their flow. Previous analytical and numerical studies have shown that the heat flux for the saturated HWI scales as the inverse of electron beta. These numerical studies, however, had limited scale separation and consequently large fluctuation amplitudes, which calls into question their relevance at astrophysical scales. To this end, we perform a series of particle-in-cell simulations of the HWI across a range of electron beta and temperature-gradient length scales under two different physical setups. The saturated heat flux in all of our simulations follows the expected inverse-electron-beta scaling, supporting the robustness of the result. We also use our simulation results to develop and implement several methods to construct an effective collision operator for whistler turbulence. The results point to an issue with the standard quasi-linear explanation of HWI saturation, which is analogous to the well-known 90-degree scattering problem in the cosmic ray community. Despite this limitation, the methods developed here can serve as a blueprint for future work seeking to characterize the effective collisionality caused by kinetic instabilities.
References in corpus (37)
- Hot Accretion Flows Around Black Holes
- Shocks and cold fronts in galaxy clusters
- X-ray Spectroscopy of Cooling Clusters
- Thermal Conduction in Clusters of Galaxies
- The multi-scale nature of the solar wind
- The Dynamical Structure of Nonradiative Black Hole Accretion Flows
- Cosmic Ray Propagation: Nonlinear Diffusion Parallel and Perpendicular to Mean Magnetic Field
- Models of Galaxy Clusters with Thermal Conduction
- Buoyancy Instabilities in Weakly Magnetized Low Collisionality Plasmas
- Alfven Wave Reflection and Turbulent Heating in the Solar Wind from 1 Solar Radius to 1 AU: an Analytical Treatment
- Kinetic turbulence in relativistic plasma: from thermal bath to non-thermal continuum
- Convective and Rotational Stability of a Dilute Plasma
- Magnetic Reconnection as the Driver of the Solar Wind
- Chandra Temperature Map of Abell 754 and Constraints on Thermal Conduction
- Electron heat conduction in the solar wind: transition from Spitzer-Härm to the collisionless limit
- Statistical Study of Whistler Waves in the Solar Wind at 1 AU
- Radiatively Inefficient Accretion Flow Models of Sgr A*
- On conduction, cooling flows and galaxy formation
- Suppression of electron thermal conduction in the high intracluster medium of galaxy clusters
- Suppression of electron thermal conduction by whistler turbulence in a sustained thermal gradient
- Self-inhibiting thermal conduction in high-beta, whistler-unstable plasma
- Hot Accretion With Conduction: Spontaneous Thermal Outflows
- Thermal Balance in the Intracluster Medium: Is AGN Feedback Necessary?
- Turbulent Mixing in Clusters of Galaxies
- The Effects of Thermal Conduction on Radiatively-Inefficient Accretion Flows
- Electron heat flux in the near-Sun environment
- Dynamical stability of a thermally stratified intracluster medium with anisotropic momentum and heat transport
- On the Growth and Saturation of the Gyroresonant Streaming Instabilities
- Resonance-broadened transit time damping of particles in MHD turbulence
- Loading Relativistic Maxwell Distributions in Particle Simulations
- Whistler-regulated MHD: Transport equations for electron thermal conduction in the high intracluster medium of galaxy clusters
- Regulation of thermal conductivity in hot galaxy clusters by MHD turbulence
- Suppressed heat conductivity in the intracluster medium: implications for the magneto-thermal instability
- Resonance frequency broadening of wave-particle interaction in tokamaks due to Alfvénic eigenmode
- Linear Vlasov theory of a magnetised, thermally stratified atmosphere
- Projection-operator methods for classical transport in magnetized plasmas. I. Linear response, the Braginskii equations, and fluctuating hydrodynamics
- Thermal conductivity with bells and whistlers: suppression of the magnetothermal instability in galaxy clusters