Modifications of plasma density profile and thrust by neutral injection in a helicon plasma thruster

Argon propellant is introduced from the upstream and downstream sides of a high powerhelicon plasma thruster. Theplasma density profile and the imparted thrust aremeasured for various upstream and downstream argonflow rates, where the total gasflow rate of 70 sccm and the resultant vacuum chamberpressure of 0.2 mTorr are maintained. It is observed that the imparted thrust increases with an increase in the downstream gasflow rate; simultaneously an upstream-peaking profile of theplasma density observed for the upstream gas injection becomes uniform for the downstream gas injection. The difference in the thrust between the upstream and downstream gas injections is enhanced by increasing the rf power. The observed density profiles are qualitatively consistent with theoretical predictions taking a neutral depletion effect into account.

Source: Applied Physics Letters - November 7, 2016 Category: Physics Authors: Kazunori Takahashi, Yoshinori Takao and Akira Ando Source Type: research