超高速碰撞产生等离子体的机理分析

Mechanism analysis of plasma generated by hypervelocity impact

用二级轻气炮开展直径为6.4 mm的球形LY12铝弹丸以不同速度撞击厚度为23 mm的LY12铝靶,得到了等离子体电子温度。提出超高速碰撞产生等离子体的剩余比内能机制和弹靶粒子二次碰撞机制,开展球形弹丸超高速碰撞靶板试验。结果表明:产生等离子体的临界碰撞速度约为4.8 km/s,与弹靶粒子二次碰撞机制相符;用电子力场方法模拟一维平面超高速碰撞,得到产生等离子体相变的临界碰撞速度为10 km/s,与剩余比内能机制相符。弹丸超高速碰撞靶板产生等离子体的机理是喷出物中弹靶粒子发生二次碰撞,使弹靶粒子剩余比内能进一步增大而发生电离。

The hypervelocity impact experiments of spherical LY12 aluminum projectile with diameter of 6.4 mm at different speeds on LY12 aluminum target with thickness of 23 mm were conducted using a two-stage light gas gun. The temporal distribution of plasma electron temperature were obtained. The residual specific internal energy mechanism of plasma produced by hypervelocity collision and the secondary impact mechanism of projectile and target particles were proposed. The hypervelocity impact experiment of spherical projectile on target plate was conducted. The results show that the critical velocity for plasma generated by hypervelocity impact is about 4.8 km/s,which is in agreement with the mechanism of second impact of projectile-target particles. The process of one-dimensional plane hypervelocity impact was simulated by using the electron force field methods,showing that the plasma phase transition occurrs obviously when the impact velocity is 10 km/s,which is consistence with the residual specific energy mechanism. The mechanism of plasma generated by hypervelocity impact is that the second impact occurred between the particles of projectile and target,which increases the residual specific internal energy of the particles of projectile and target and also makes the particles ionized.