2D radiation-hydrodynamics modeling of laser-plasma targets for ion stopping measurements

Two-dimensional radiation hydrodynamics calculations were performed to analyze how a homogeneous plasma layer for ion-stopping measurements can be created by direct laser irradiation of thin carbon foils. At the initial stage, the assumed (so as to imitate the discussed experimental conditions) strongly non-uniform intensity distribution in the laser spot leads to the formation of relatively dense and cold clumps in the plasma. However, it is shown that after several nanoseconds the clumpy structure dissipates predominantly due to the energy transport by thermal radiation. Laser irradiation schemes with the fundamental and doubled frequency light, as well as one- and two-sided heating of the target foil are analyzed and compared. We find that the two-sided irradiation with the doubled laser frequency creates a fully ionized plasma layer and allows to reduce the plasma column-density variations to a level of ≲1%.