Development of Two Propulsion Systems with Helicon Plasma

Two space propulsion systems, which are called K2H (KBSI-KAIST-Hanyang University) and DiPS (Diversified Plasma Simulator) devices, are being developed in parallel to explore the space propulsion parameters and optimal helicon operation conditions with the concept of VASIMR (Variable Specific Impulse Magnetoplasma Rocket). Both devices utilize the open-ended magnetic configuration. K2H has three regions such as helicon source, ion cyclotron resonance heating (ICRH), magnetic nozzle and expansion regions. DiPS is the space plasma simulator and composed of three major sections: helicon plasma source, extraction region and space simulation region. Helicon plasmas are generated for both devices by 13.56 MHz rf power using M=+1 right-helical antenna at pressure of several mTorr. Initial plasma parameters such as density, temperature, and drift velocity were measured by a laser induced fluorescence (LIF) system and a fast scanning electric probe system with an rf-compensated Langmuir probe and a Mach probe at ICRH and magnetic nozzle region. The results are given as follows: plasma density n = 10¹¹ - 10¹³ cm^-3 (K2H) and 10¹² - 10¹³ cm^-3 (DiPS), electron temperature T_e = 3 - 9eV (K2H) and 2 - 4 eV (DiPS), ion temperature T_i = 0.144 - 0.164 eV (K2H), and drift velocity v_d = 0.8 - 1.55 km/s (K2H). A simple analysis of the results is provided.