Analysis of the performance of a multistage railgun

In a previous paper (see IEEE Trans. Magn., vol.37, p.445-449, Jan. 2001), the authors proposed a "multistage" railgun configuration in order to reduce the negative effects of the ablation of material from the rail and insulator walls on the velocity of the mass to accelerate. The railgun was segmented in some stages and the accelerating pellet is pushed by a new plasma armature at every stage. For a given size of the rail, the multistage configuration reached a velocity about 20% higher than the one in the single stage, with different mass of the pellet, reducing the ablated mass. The aim of this paper is to perform a deeper analysis of the performance of the multistage railgun in order to characterize the values of the quantities influencing the performances of the railgun in terms of velocity of the pellet. In particular, a series of simulations has been carried out varying the feeding currents, pellet masses, arc masses, and compositions of the propelling plasma arc. The influence of these quantities has been analyzed in order to study the velocity of the pellet mass and the behavior of the plasma arc in terms of ablated mass, temperature, pressure, and conductivity at every stage.