• DOI:10.1111/J.1365-2966.2004.08329.X
• Corpus ID: 8256849

Radiative heat conduction and the magnetorotational instability

@article{ArayaGchez2002RadiativeHC,
  title={Radiative heat conduction and the magnetorotational instability},
  author={Rafael Angel Araya-G{\'o}chez and Ethan T. Vishniac},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2002},
  volume={355},
  pages={345-351}
}

• R. Araya-Góchez, E. Vishniac
• Published 31 July 2002
• Physics
• Monthly Notices of the Royal Astronomical Society

A photon or a neutrino gas, semicontained by a non-diffusive particle species through scattering, comprises a rather peculiar magnetohydrodynamic fluid where the magnetic field is truly frozen only to the comoving volume associated with the mass density. Although radiative diffusion precludes a formal adiabatic treatment of compressive perturbations, we cast the energy equation in quasi-adiabatic form by assuming a negligible rate of energy exchange among species on the time-scale of the perturbation. This leads to a simplified dispersion relation for toroidal, non-axisymmetric magnetorotational modes when the accretion disc has comparable stress contributions from diffusive and non-diffusive components. The properties of the modes of fastest growth are shown to depend strongly on the compressibility of the mode, with a reduction in growth rate consistent with the results of Blaes & Socrates for axisymmetric modes. A clumpy disc structure is anticipated on the basis of the polarization properties of the fastest-growing modes. This analysis is accurate in the near-hole region of locally cooled, hyper-accreting flows if the electron gas becomes moderately degenerate such that non-conductive, thermalizing processes with associated electron–positron release (i.e. neutrino annihilation and neutrino absorption on to nuclei) are effectively blocked by high occupation of the Fermi levels.