Helicon double layer thruster operation in a low magnetic field mode

• Published in: Plasma sources science & technology 2013-02, Vol.22 (1), p.015015-1-7
• Main Authors: Harle, T, Pottinger, S J, Lappas, V J
• Format: Article
• Language: English
• Subjects: Density; Double layer; Flow rate; Magnetic fields; Propellants; Strength; Thrust; Thrusters
• ISSN: 0963-0252; 1361-6595
• DOI: 10.1088/0963-0252/22/1/015015

Direct thrust measurements are made of a helicon double layer thruster operating in a low magnetic field mode. The relationship between the imposed axial magnetic field and generated thrust is investigated for a radio frequency input power range 200-500 W for propellant flow rates of 16.5 and 20 sccm (0.46 and 0.55 mg s−1) of argon. The measured thrust shows a strong dependence on the magnetic field strength, increasing by up to a factor of 5 compared with the minimum thrust level recorded. A peak thrust of 0.4-1.1 mN depending on thruster operating conditions is obtained. This increase is observed to take place over a small range of peak magnetic field strengths in the region of 70-110 G. The magnitude of the thrust and the corresponding magnitude of the magnetic field at which the peak thrust occurs is shown to increase with increasing input power for a given propellant flow rate. The ion current determined using a retarding field energy analyser and the electron number density found using a microwave resonator probe both correlate with the observed trend in thrust as a function of applied magnetic field.