A cold ionospheric plasma has electron density and electron temperature (

PHYSICS · Multi-part · Fermi University Physics · Plasma Physics · Kinetic theory, collisions and transport · Kinetic theory, collisions and transport

Plasma Physics, Ch Coulomb collisions: the Coulomb logarithm, the Fokker-Planck equation and Spitzer resistivity

Problem

A cold ionospheric plasma has electron density ne=1.0×1012 m−3n_e = 1.0\times10^{12}\,\mathrm{m^{-3}} and electron temperature Te=0.20 eVT_e = 0.20\,\mathrm{eV} (Z=1Z=1, singly ionised background). ((a)) Calculate ln⁡Λ\ln\Lambda, choosing the correct short-distance cutoff between b90b_{90} and ℏ/mevte\hbar/m_ev_{te}. ((b)) Using Braginskii's τe=62π3/2ϵ02me1/2Te3/2/(niZ2e4ln⁡Λ)\tau_e = 6\sqrt{2}\pi^{3/2}\epsilon_0^2m_e^{1/2}T_e^{3/2}/(n_iZ^2e^4\ln\Lambda), calculate the electron-ion deflection time at the thermal speed.

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