2D CFD simulation and optical diagnose on density profile for multisized conical supersonic gas-jet nozzles

With the rapid development of laser wakefield acceleration, researchers have set higher standards for the target parameters of generating plasma through interactions with lasers. Among these targets, supersonic gas targets have been widely used in laser wakefield electron accelerators, offering unique advantages in improving the quality of electron beams. Therefore, it is essential to gain a deep understanding of the physical properties such as density and velocity of these gas jets. <br/><br/> In the study of supersonic gas-jet target characteristics, computational fluid dynamics (CFD) simulations provide convenient and rapid means to obtain parameters. To verify the accuracy of the CFD simulations, it is necessary to crosscheck the simulation results with optical diagnostic experiments. In this paper, based on an independently set-up Nomarski interference system, we obtained the supersonic gas-jet density profile produced by two types of nozzles (with throat size 0.5 mm diameter, outlet size 1 mm and 2 mm diameter), and compared them with the CFD results using Ansys Fluent. The results showed order of magnitude consistency between the simulations and the experiments, indicating that the gas target density parameters obtained through CFD are reliable. The experimental part of this paper utilized the phase difference to obtain the gas density profile through Abel inversion. It can be seen that CFD simulation provides a reliable means of data acquisition and validation for LWFA.