Patent ID: 7294969

Claim:
A high-frequency discharge plasma generation-based two-stage Hall-effect plasma accelerator comprising an ion acceleration section, and a high-frequency wave supply section for supplying a high-frequency wave to said ion acceleration section, said ion acceleration section including: an annular acceleration channel comprising two concentric cylindrical structures different in radius and a space defined between said concentric cylindrical structures, said concentric cylindrical structures having a first end formed as an open end for ejecting an ion therefrom and a second, opposite, end located adjacent to said high-frequency wave supply section; a gas inlet port connected to said annular acceleration channel at a position adjacent to said high-frequency wave supply section to introduce a plasma-generating gas from the outside to the inside of said annular acceleration channel; an anode disposed in the space of said annular acceleration channel at a position adjacent to said high-frequency wave supply section; a cathode disposed in the vicinity of said first open end of said annular acceleration channel and adapted to have an acceleration voltage to be applied at a given level with respect to said anode; a neutralizing electron generation portion adapted to generate an electron for neutralizing the ion ejected from said annular acceleration channel; magnetic-field generation means for generating a magnetic field having a given intensity distribution in the radial direction from the central axis of said annular acceleration channel; and high-frequency wave generation means for generating a high-frequency wave to be introduced in the space of said annular acceleration channel, whereby: said plasma-generating gas introduced from said gas inlet port into the space of said annular acceleration channel is ionized by the high-frequency wave supplied from said high-frequency wave supply section to generate plasma; a positive ion included in said generated plasma is accelerated in the space of said annular acceleration channel toward said first open end by said acceleration voltage applied between said anode and said cathode, and ejected outside; and an electron included in said generated plasma is restricted in its movement in the axial direction of said concentric cylindrical structures by an interaction with said radial magnetic field, said high-frequency wave supply section including high-frequency wave introduction means for introducing the high-frequency wave generated by said high-frequency wave generation means, into the space of said annular acceleration channel, wherein: said ion acceleration section is operable to control a degree of said ion acceleration in accordance with said acceleration voltage serving as an acceleration control parameter; and said high-frequency wave supply section is operable to control an amount of said plasma generation in accordance with said high-frequency wave output serving as a plasma-generation control parameter to be controlled independently of said acceleration control parameter.