Mechanism And Experiment Investigation Of Ablation Mode For Laser Propulsion

Laser propulsion, which works on the counterforce generated during the interaction between high-power laser and propellant, is a new concept technique for propulsion. Compared with traditional chemical propulsion, the main innovation in concept of laser propulsion reduces to two separations: separation of energy and material, and separation of aero-craft and energy source system. In general, there are two main modes, the rocket ablation mode and the air-breathing mode, which divided by whether consume the taking material or not. In the present thesis, it focuses on the ablation mode laser propulsion, physical and mechanical mechanism of ablation mode laser propulsion have been studied by model analysis, numerical simulation and experiment study, some main conclusions are reached and will be listed as follows.The principle of ablation laser propulsion (ALP) was analyzed on the dynamic physical processes of laser target interaction, and can be divided into three stages. The process of vapour of solid target surface material; the process of temperature rise and ionization of target vapor under interaction with laser pulse; the process of free expand movement of plasma. The ablation pressure and mechanical coupling coefficient are the important parameters of laser propulsion. The mechanics propulsion efficiency model based on LSD (laser supported detonation) was detailed analyzed.1 -D radiation-hydrodynamic code MEDUSA was introduced, and presented the main floe chat of MEDUSA. The dynamic physical process of single-pulse laser interaction with solid target was simulated by use of MEDUSA code; the parameters of ablated plasma (particle velocity, density, temperature) variety of time and space were obtained, and presented the pressure of ablated surface (the surface of laser target interaction) variety of time during the laser pulse. The impulse solid target obtained can calculate by integral the pressure of time, thus can calculate the mechanical coupling coefficient c_m. The propulsion efficiency of Al target and C-H target of different laser parameters were simulated, and compared with experiments and empirical model results, which showed that the simulated results were believable.A general Godunov finite difference schemes-WENO (Weighted Essentially Non-Oscillatory) schemes which have fifth-order accuracy is used to make a numerical calculation for 2-dimensional axis symmetrical laser-supported plasma flow field under laser ablated solid target and laser ablated propulsion efficiency...