Self-inhibiting heat flux

Abstract

Heat transfer through weakly magnetized diffuse astrophysical plasmas excites whistlers. This leads to electron whistler resonant scattering, a reduction of the electron mean free path, and heat flux inhibition. However, only whistlers propagating at a finite angle to the magnetic field (off-axis) can scatter the heat flux carrying electrons. Thus the level of heat flux inhibition along the magnetic field lines depends on the presence of off-axis whistlers. We obtain a solution of the Boltzmann equation with the whistler wave equation and show that if ∈thβe ≫ 10-4, where ∈th is the thermal collisional Knudsen number and βe is the ratio of the electron pressure to the magnetic energy density, then scattering of heat flux carrying electrons by off-axis whistlers, which are shown to propagate at about 65°, is efficient enough to lead to heat flux inhibition along field lines. The inhibition so obtained is proportional to (∈thβe)-1.