On the electrodeless MPD thruster using a compact helicon plasma source

Helicon wave excitation is one of the promising RF plasma production methods. It produces high density plasma (∼10¹³ cm^-3) that enables electromagnetic acceleration. We prepared the acceleration coil or 2 pairs of copper plates around the glass tube. These acceleration methods are called a repetitious coil current acceleration and a continuous "Lissajous" acceleration, respectively. When the repetitious coil acceleration was applied, the maximum plasma velocity of 3.6 km/s was 76% velocity increment compared with before acceleration with the absorbed plasma production + acceleration power of (400+180) W and the applied magnetic field strength of 1,450 gauss. As for the "Lissajous" acceleration, the plasma velocity was 2.2 km/s with the absorbed plasma production + acceleration power of (290+200) W. However it is suggested that these accelerations remain in the thermal acceleration regime judging from the electron temperature or density increase.