Ionization and radiation dynamics of carbon ablation plasmas

Abstract

A computational model that can be used for studying the ablation physics of medium z targets by ion beams is presented. In particular, the interaction of a proton beam as it heats and ablates a carbon target is analyzed. Because the radiation emitted during the interaction can carry away a significant amount of the total target energy, the radiation and ionization dynamics is treated carefully. This is accomplished by incorporating a collisional‐radiative equilibrium model into the ionization dynamics package of a one‐dimensional hydrodynamics model. Cold target energy deposition is assumed, thus eliminating the need for resolving the energy deposition after each time step. The errors incurred by this assumption are discussed. The computer simulation is applied to a general parameter study that involves varying the initial beam conditions to see effects upon the evolution of the target. In addition, the amount of Kα radiation produced by the direct interaction of the beam particles with the individual target atoms is calculated. This information is useful for diagnostic purposes since it is highly dependent upon the ionization state of the target.