Development of Miniature Radio Frequency Ion Thruster with Inductively Coupled Plasma Source

This study investigated an inductively coupled plasma (ICP) as an ion source. This ICP source can produce high-density plasma and has high propellant utilization efficiency and low power consumption. The ICP source was induced by a 13.56-MHz electromagnetic field and by supplying argon propellant gas into the radio frequency (RF) ion thruster at low gas pressures. The ions were accelerated along the electrostatic field gradient by using a potential bias to form an ion beam. SIMION was used to simulate the trajectory and distribution of the ion beam. An electron-emitting neutralizer must be located downstream of the thruster to neutralize the potential of the ion thruster. A Langmuir probe was used to measure the electron temperature and plasma density. A Faraday cup was used to determine the ion current of the ion thruster. The parameters of the ICP ion source and the performance of the ion beam were evaluated using the measurement systems. The miniature RF ion thruster achieved 1200–1633 s of specific impulse and 7.6-13.8 mN of thrust at 80 W of total input power. The thruster efficiency was 10 %-13 %, and the mass utilization efficiency was 12 %–16 %.