Generation and stopping of laser-driven two-component ion beam

Abstract

The generation and stopping of a laser-driven two-component ion beam are investigated by three-dimensional particle-in-cell simulation and an extended stopping model. It is found that a two-component ion beam with the tunable composition ratio can be obtained from the two-species-ions sandwich target interacting with a relativistic laser pulse. When the generated proton beam mixed with a certain portion of carbon ions is transporting in fully ionized dense plasma, the beam stopping power is significantly enhanced compared to a pure proton beam. The maximum penetration depth is sharply reduced, and the Bragg peak with a higher magnitude appears earlier at the end of their paths, which is beneficial for achieving more localized energy deposition. The effect of heavy ion mixing on proton beam driven fast ignition is also discussed. A simple theoretical model is established, indicating that the required ignition time is relatively delayed for a heavy-ion doping case. For a small hot-spot size, it is possible to achieve the fusion ignition for a low mixed ratio. However, it is difficult to maintain a high fuel temperature due to the growing energy loss originating from mechanical work and thermal conduction.