Gas jet target with controllable density via throat diameter of conical nozzle

Abstract A supersonic gas jet has been a special target in the ultraintense laser interaction field due to its controllable atomic density distribution. This work investigates the spatial atomic density distribution in argon gas jets ejected from conical nozzles with different throat diameters. Both experiment and simulation results show that the atomic density and its distribution can be controlled by changing the throat diameter of the conical nozzle. The quantitative dependence of atomic density on the throat diameter under different backing pressures is obtained. It also agrees with that from the one-dimensional gas dynamics model. However, it is noted that for a large throat diameter at a high gas backing pressure, a radial saddle-shaped atomic density profile is demonstrated experimentally within a few millimeters away from the nozzle outlet. The results are helpful to optimize the density profile in gas-jet targets and to understand the effect of the throat diameter of the conical nozzle on cluster size in Hagena scaling law.