Space Simulation Testing of the Helicon Double Layer Thruster Prototype

A prototype of the Helicon Double Layer Thruster (HDLT), a new magnetoplasma thruster that produces a high velocity collimated ion beam using a current-free double layer, has been tested and characterised for the first time inside a space simulation vacuum chamber. The first experimental evidence of the double layer and associated ion beam with the HDLT prototype immersed in vacuum has been obtained. When using argon, the plasma and ion beam have been investigated with a retarding field energy analyser (RFEA), a Langmuir probe and with a new high sensitivity momentum flux measuring instrument (MFMI) designed to measure the thrust imparted by the exhaust of the HDLT prototype. When using xenon and increasing the RF power applied to the HDLT prototype, a new high density ‘blue’ mode has been observed. This mode occurs when the plasma source transitions from a capacitively coupled to what may be a helicon wave-sustained mode. The mode transition is accompanied by a significant increase in the plasma density and the appearance of a bright white/blue plasma. The mode has been investigated with the RFEA, Langmuir probe and MFMI and it has been shown that the thrust produced by the HDLT prototype increases in this mode.