Application to Space Propulsion with Ablation Plasma Produced by Pulsed Ion Beam

Abstract

In this paper, we showed the performance of a propulsion system in space by ablation plasma produced by pulsed ion beam and its controllability. First, the fundamental study of flyer acceleration with ablation plasma produced by irradiation of an intense pulse ion beam was explained numerically. Here, we used a one-dimensional hydrodynamic model based on the stopping power taking the interaction between the flyer material and ion beam into account. Using this numerical model, a maximum flyer velocity of about 8 km/s and ablation pressure of 20 GPa could be obtained at the ion beam energy density of 4 kJ/cm2 and the pulse width of an incident ion beam of 60 ns. Moreover, our numerical results agreed well with experimental ones. From these results, we could estimate performance of the space propulsion system with ablation plasma produced by pulsed ion beam which is an impulse bit of 2000 Ns/m2 and a specific impulse of about 5000-6000 seconds at the ion beam energy density of 4 kJ/cm2 and the pulse width of an incident ion beam of 60 ns. In addition, this paper also discussed the controllability of impulse bit, and specific impulse and we finally found that changing ion beam acceleration voltage, energy density, power density, and the duration of ion beam irradiation could control both performances. Furthermore, we found that the important factors are to control the acceleration voltage and pulse width in order to improve the space propulsion performance of this system.