Process and apparatus for igniting an ultra-high frequency ion source

Claim 1

An ignition device of an ultra-high frequency ion source using a resonant cavity having a random shape, supplied by a gas or a vapor of a material intended to form a plasma filling the cavity, a system having a waveguide for injecting ultra-high frequency power into the cavity and a system for extracting ions from the plasma outside the cavity, wherein: each of the three dimensions of the plasma cavity, namely length, width and height or diameter and length exceeds the small side or diameter of the waveguide of the system for injecting ultra-high frequency power into the cavity; means are provided for injecting into the cavity gas or vapor of the material to be ionized upstream of the ion extraction system and at a relatively small distance from the latter compared with the length of the cavity in order to establish a pressure gradient in the source, said pressure rising from the ultra-high frequency power injection zone to the ion extraction zone; means are provided for producing within the medium to be ionized in a region of the cavity preferably located at a few centimeters downstream of the junction zone between the ultra-high frequency power injection system and the cavity, electron nuclei bringing about the ignition of the plasma having a random shape, the dimensions of the enclosure and the rising pressure of the injection system towards the extraction point then enabling the plasma to function under multimode operating conditions, i.e. without a privileged mode, and to self-maintain with the aid of the ultra-high frequency power alone, without having recourse to a permanent cyclotron resonance of the electrons of said plasma.