2015 年 10 巻 p. 3401037
To investigate characteristics and estimate propulsion performance of a high-density radio frequency plasma with a very small diameter, we have developed the Small Helicon Device (SHD) and measured an electron density ne, an ion velocity vi and an emission intensity of ArII under various conditions such as a discharge diameter (down to 3 mm), a mass flow rate and a gas species. Using quartz discharge tubes with inner diameter (i.d.) of 3, 10, 20 mm with an Ar gas, ne of (2.5 - 6) × 1012 (estimated from optical measurement), ∼2.5 × 1012 and ∼2.0 × 1012 cm−3, respectively, at −40 mm downstream from an excitation antenna was obtained. Using the 20 mm i.d. tube with a H2 gas, vi ∼40 km/s was achieved in the presence of the magnetic field gradient.
