||Neutral-depletion-induced axially asymmetric density in a helicon source and imparted thrust
Takahashi, Kazunori ,
Takao, YoshinoriAndo, Akira
074103-4 , 2016-02-15
The high plasma density downstream of the source is observed to be sustained only for a fewhundreds of microsecond at the initial phase of the discharge, when pulsing the radiofrequencypower of a helicon plasma thruster. Measured relative density of argon neutrals inside the sourceimplies that the neutrals are significantly depleted there. A position giving a maximum plasmadensity temporally moves to the upstream side of the source due to the neutral depletion and thenthe exhausted plasma density significantly decreases. The direct thrust measurement demonstratesthat the higher thrust-to-power ratio is obtained by using only the initial phase of the high densityplasma, compared with the steady-state operation.