Abstract: The energy of positive ions accelerated in laser-matter interaction experiments can be significantly increased by providing a plurality of laser pulses, e.g., through the process of splitting the incoming laser pulse, to form multiple laser-matter interaction stages. From a thermodynamic point of view, the splitting procedure can be viewed as an effective way of increasing the efficiency of energy transfer from the laser light to positive ions, which energy peaks for processes having the least amount of entropy gain. A 100% increase in the energy efficiency is achieved for a six-stage laser positive ion accelerator compared to a single-stage laser positive ion accelerator.

Abstract: The energy of positive ions accelerated in laser-matter interaction experiments can be significantly increased by providing a plurality of laser pulses, e.g., through the process of splitting the incoming laser pulse, to form multiple laser-matter interaction stages. From a thermodynamic point of view, the splitting procedure can be viewed as an effective way of increasing the efficiency of energy transfer from the laser light to positive ions, which energy peaks for processes having the least amount of entropy gain. A 100% increase in the energy efficiency is achieved for a six-stage laser positive ion accelerator compared to a single-stage laser positive ion accelerator.

Abstract: 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.