Impact of magnetic field on the parallel resistivity.

The impact of magnetic field (MF) on the parallel resistivity η_{∥} is studied for strongly magnetized plasmas with the electron thermal gyroradius ρ_{the} smaller than the Debye length λ_{D} but much larger than the Landau length λ_{L}. Two previous papers [P. Ghendrih et al., Phys. Lett. A 119, 354 (1987)10.1016/0375-9601(87)90614-1; S. D. Baalrud and T. Lafleur, Phys. Plasmas 28, 102107 (2021)10.1063/5.0054113] found η_{∥} to increase monotonically with MF. Unfortunately, both works used predetermined electron distribution functions and are thus not self-consistent. In this paper, we analyze the MF dependence of η_{∥} self-consistently by solving the electron magnetized kinetic equation in a Lorentz gaslike approximation. It is found η_{∥} decreases monotonically with MF, with λ_{D} in the usual Coulomb logarithm lnΛ=ln(λ_{D}/λ_{L}) being replaced by ρ_{the}. The underlying physics is that the electrons affected only by the collisions with impact parameters between λ_{L} and ρ_{the} carry almost all the parallel current.