The effect of viscosity of liquid propellant on laser plasma propulsion

The effect of viscosity on the coupling coefficient and specific impulse is investigated with water and glycerol as propellants in laser plasma propulsion. It is found that the propulsion is much more correlated with the liquid viscosity. For water in particular, the coupling coefficient and specific impulse presents nearly a linear relationship with the viscosity. The weak dependence of the coupling coefficient on the laser energy at a high viscosity is observed. These results indicate that a liquid propellant with suitable viscosity can be used in laser plasma thruster.