Collisional Damping of Transverse Waves in a Plasma

The Landau (Fokker‐Planck) equation is used to calculate the temporal damping rate for the small amplitude, transverse electromagnetic mode (linearly polarized) for (a) no external fields, and (b) a uniform magnetic field. In (a) the damping rate is found by using a solution to the kinetic equation to evaluate the electron current. This damping may be recovered from the zero field limit of a previous result of Buti for the right circularly polarized mode after a correction is made in that result. In (b) a moment equation approach is used, and the heat flow tensor components are evaluated using a solution to the kinetic equation. The damping rate is ωI ≃ −12(2π)1/2ωp3ω02ln ΛΛ[1 − λD2k2ωp4ω02(ω02 − Ω02)2(2ω02 − Ω02) + 2λD2k2ωp25(ω02 − Ω02)2(5ω02 + Ω02 + 32 (ω02 + Ω02))], where ω02 = c2k2 + ωp2. The damping in (b) depends on the magnetic field only in the thermal correction, and reduces to that in (a) when magnetic effects are negligible.