Fig. 6
From: Experimental demonstration of tractor millimeter wave beam propulsion
Momentum coupling coefficient \(C_m\) and plasma structure with different lenses. The momentum coupling coefficients are evaluated by a pendulum-type impulse measurement device. The hollow observation window is removed from the thruster, and the integral images are captured by a digital camera. The beam powers, pulse widths \(\tau\), and focal lengths of the PTFE lens F are changed to understand the parameter dependence of propulsive performance and plasma structure.
