## Info

dE E

where the variations of the particle energies is the course of movement in the electric field is automatically included. The resultant equation involving the equilibrium distribution function (including Io = const) is

With boundary conditions n(Einj-) = ninj- and Io = n(Eo\eo/mac (here Eo is the energy of ejection from the sheet). The first term in Eq. 4.18.21 describes the conventional diffusion, the second term is identical with the thermo-diffUsion (see §11 in Lifshitz and Pitaevsky, M1979) due to the particle energy dependence of the diffusion coefficient. The solution of Eq. 4.18.21 is (Pustil'nik, 1978):