TARGET DESIGN FOR HIGH-POWER LASER ACCELERATED IONS

摘要

Methods for designing a laser-accelerated ion beam are disclosed. The methods include modeling a system including a heavy ion layer, an electric field, and high energy light positive ions having a maximum light positive ion energy, correlating physical parameters of the heavy ion layer, the electric field, and the maximum light positive ion energy using the model, and varying the parameters of the heavy ion layer to optimize the energy distribution of the high energy light positive ions. One method includes analyzing the acceleration of light positive ions, for example protons, through interaction of a high-power laser pulse with a double-layer target using two-dimensional particle-in-cell (PIC) simulations and a one-dimensional analytical model. The maximum energy acquired by the accelerated light positive ions, e.g., protons, in this model depends on the physical characteristics of the heavy-ion layer-the electron-ion mass ratio and effective charge state of the ions. The hydrodynamic equations for both electron and heavy ion species solved and the test-particle approximation for the protons is applied. It was found that the heavy ion motion modifies the longitudinal electric field distribution, thus changing the acceleration conditions for the light positive ions.