Abstract:

Laser-driven in-tube accelerator is a new-style laser propulsion thruster characterized by accelerating projectile in a tube. With the ray tracking method, tracks of the rays in the grid are used to compute the energy source term by radiation transfer equation. The control equations with energy source term are solved numerically, through which the features of the generation and evolvement of the laser-induced shock waves in the tube are studied. Processes including air optical breakdown, absorption of laser energy, plasma shielding of the laser beam and thrust forming are reproduced. Numerical results indicate that the obtained momentum coupling coefficient is 3.61×10-4 N/MW，and the conversion efficiency of plasma internal energy to fluid kinetic energy is about 9%。

Key words: laser propulsion, laser-driven in-tube accelerator, ray tracking method, energy source term, numerical simulation