Plasma gun and methods for the use thereof

A high PRF thruster for use in a substantially vacuum environment comprising:

• a center electrode;
• an outer electrode substantially coaxial with said center electrode, a coaxial column being formed between said electrodes, which column has a closed base end and an open exit end;
• an inlet mechanism for introducing a selected gas into the base end of said column;
• a plasma initiator at said base end;
• and
• a solid state, high repetition rate pulsed diver operable concurrent with plasma initiation at the base of said column for delivering a high voltage pulse across said electrodes, the plasma expanding from the base end of the column and off the exit end thereof, the voltage of each pulse decreasing over the duration of the pulse, with the pulse voltage and electrode length being such that the voltage across the electrodes reaches a substantially zero value as the plasma exits the column.

A high PRF source for EUV radiation comprising:

• a center electrode;
• an outer electrode substantially coaxial with said center electrode, a coaxial column being formed between said electrodes, which column has a closed base end and an open exit end;
• an inlet mechanism for introducing a selected gas into said column;
• a plasma initiator at the base end of said column, and
• a solid state, high repetition rate pulsed diver operable on plasma initiation at the base of said column for delivering a high voltage pulse across said electrodes, the plasma expanding from the base end of the column and off the exit end thereof, the current for each voltage pulse initially increasing to a maximum and then decreasing to zero, the pulse voltage and electrode lengths being such that the current for each pulse is at substantially its maximum as the plasma exits the column.

A method for utilizing a plasma gun having a center electrode and an outer electrode substantially coaxial with said center electrode, a coaxial column being formed between said electrodes, which column has a closed base end and an open exit end, as a high PRF thruster to provide a selected thrust in a substantially vacuum environment, comprising the steps of:

• (a) valving a selected gas into the base end of said column;
• (b) charging a solid state, high repetition rate pulsed driver to a selected high voltage, said voltage being applied across the electrodes;
• (c) initiating plasma breakdown at said base end when said driver is substantially at said selected voltage, the plasma expanding from the base end of the column and being exhausted from the exit end of the column at high exhaust velocity substantially concurrent with the charge becoming fully discharged;
• and
• (d) repeating steps (b) and (c) at high PRF until said selected thrust has been achieved.