Nonlinear stopping power of ions in plasmas

The study of the nonlinear stopping power of ions in plasmas is of fundamental importance for various applications. One example is the energy loss of heavy ions passing through a plasma. Due to the high non-equilibrium charge states specific to heavy ions, the plasma regime with coupling parameters 1/N-D < 1 and Z(p)/N-D greater than or similar to 1 (N-D similar to number of electrons in a Debye sphere, Z(p) charge of the ion) is of interest. In this regime, the Vlasov-Poisson system cannot be linearized, rather a fully nonlinear,treatment is required. In the present paper, the Vlasov-Poisson system is solved numerically by using the capability of the new generation of massively parallel supercomputers. The results are compared with the standard dielectric theory and a recent binary collision approach. It is demonstrated that nonlinear effects lead to a strongly reduced Bragg-peak for Z(p)/ND greater than or similar to 1. In the nonlinear regime, the scaling of the stopping power is close to a Z(p)(3/2) law, which is found to be characteristic for the nonlinear stopping power, if the influence of close collisions on the induced potential is treated properly. (C) 1996 American Institute of Physics.