Modified Dechanneling Theory and Diffusion Coefficients

A new type of dechanneling theory is presented by constructing a Fokker-Planck equation. The damping term, which is not renormalized to the diffusion coefficient, and a new term in addition to the usual diffusion equation appear in the Fokker-Planck equation. Making use of the general expression of the diffusion coefficient given by Ohtsuki, some simple analytic expressions for diffusion coefficients due to the many-phonon excitations, the one-electron excitation, and the plasmon excitation are presented.