Collisional Damping of Plasma Oscillations

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Abstract
An analysis of electrostatic oscillations in a weakly ionized plasma is based on the Boltzmann‐Vlasov (BV) equation with electron‐neutral collisions accounted for by a simplified form of the Lorentz‐gas Boltzmann‐collision integral. The isotropic scattering contribution to the collision integral is treated exactly while the anisotropic scattering contribution is approximated by assuming a weakly anisotropic electron velocity distribution. The collisional damping decrement is found to be equal to −ν1/2+3ν1k2v t2/ωp2− (11/3)ν2k2vt2/ ωp2 to second order in the wave number k where vt is the electron thermal velocity, ωp is the plasma frequency, and ν1 and ν2 are precisely defined averages of the collision frequency for momentum transfer. An alternative method of analysis based on the simultaneous used of the BV equation and the moment equations is also illustrated.