Experimental Research on Discharge Mode of Helicon Plasma Thruster

Research on helicon plasma propulsion mainly includes radio frequency (rf) power coupling, magnetic confinement, discharge mode. The great advantage of helicon plasma propulsion is its high plasma density. Radial velocity can be converted to axial velocity to enhance the thrust with a magnetic nozzle. The plasma density jumps during the plasma discharge is the vital judgment for helicon discharge mode. The article illustrates the apparatus of helicon plasma thruster and points out that there should be two plasma density jumps to verify the helicon discharging mode, and analyzes the plasma density collected by Langmuir probe. Meanwhile, the ion current of plasma flow is collected with retarded potential analyzer, and it clearly shows that there are two jumps in ion currents. The discharging images are taken for the capacitive discharging mode, inductive discharging mode and helicon discharging mode, respectively. Parameters for the discharging mode switch are acquired which will support the development of helicon plasma propulsion.