Theoretical model for plasma expansion generated by hypervelocity impact

Abstract

The hypervelocity impact experiments of spherical LY12 aluminum projectile diameter of 6.4 mm on LY12 aluminum target thickness of 23 mm have been conducted using a two-stage light gas gun. The impact velocity of the projectile is 5.2, 5.7, and 6.3 km/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., (Te, ne) ∝ vp3. Based on the experimental results, a theoretical model on the plasma expansion is developed and the theoretical results are consistent with the experimental data.

A 3D measuring method of magnetic properties of impact-generated plasmas

“…Close et al conducted hypervelocity impact experiments at a Van de Graaff dust accelerator with speeds from 1 km s −1 to 50 km s −1 , measured the electromagnetic pulses (EMPs) and radio frequency (RF) produced by plasmas in the hypervelocity micro particle (mass <1 ng) impact, and believed that the EMPs might cause electrical effects on spacecraft system [4,[12][13][14]. Ju et al proposed a theoretical model for plasmas expansion in hypervelocity impact based on the experimental results and found the threshold for plasmas phase transition of the aluminum single crystal using numerical simulation (molecular dynamics) from 2014 to 2015 [15,16]. Tang detected the magnetic intensity of plasmas in hypervelocity impact experiments at velocities of 5.90 and 5.95 km s −1 employing a designed coil with incidence angles of 45°, 60° and 90°, respectively [17].…”