CHARGE-STATE FLUCTUATIONS - A MASTER EQUATION APPROACH

A stochastic theory of charge exchange fluctuations in ion transport i s introduced based on a master equation for the probability of finding ions in appropriate phase space locations, When energy losses are abs ent, a forward master equation is obtained which is solved exactly in the binary charge state case, The equilibrium probability distribution is shown to be a binomial distribution and differs from that at small depths. In the more general case a backward master equation is derive d for the multi-point probability distribution function, from which an equation for the average charge state is obtained.