Theoretical model for plasma expansion generated by hypervelocity impact

The hypervelocity impact experiments of spherical LY12 aluminum projectile diameter of 6.4mm on LY12 aluminum target thickness of 23mm have been conducted using a two-stage light gas gun. The impact velocity of the projectile is 5.2, 5.7, and 6.3km/s, respectively. The experimental results show that the plasma phase transition appears under the current experiment conditions, and the plasma expansion consists of accumulation, equilibrium, and attenuation. The plasma characteristic parameters decrease as the plasma expands outward and are proportional with the third power of the impact velocity, i.e., (T_e, n_e)∞v_p³. Based on the experimental results, a theoretical model on the plasma expansion is developed and the theoretical results are consistent with the experimental data.