Analytical model for calculating laser ablation impulse coupling coefficient

Laser radiation has been considered as one kind of feasible methods to clean space debris. Impulse coupling coefficient is an important parameter to calculate the clean effects. An analytical model for calculating laser ablation impulse coupling coefficient is put forward. The impulse coupling coefficients in vapor mechanism and plasma mechanismare connected by the ionization fraction. Therefore, a unified model of impulse coupling coefficient is set up. The relationship of laser intensity, ionization fraction and impulse coupling coefficient is obtained with Al, the most common material of space debris, as the calculation example. The transition between vapor mechanism and plasma mechanism progressively changes with the increase of laser intensity. The ionization fraction is also increasing until the vapor is totallyionized. The impulse coupling coefficient increases at first, then reaches the maximum, and decreases at last. The optimum impulse coupling coefficient is obtained when the plasma mechanism dominates.