Glow plasma trigger for electron cyclotron resonance ion sources

Area of Science:

• Physics
• Plasma Physics
• Ion Source Technology

Background:

• Electron cyclotron resonance ion sources (ECRISs) are vital for generating high-current, multicharged ion beams in nuclear, atomic, and high-energy physics.
• Achieving high charge states in ECRISs necessitates low gas pressure, which paradoxically increases microwave discharge development time, hindering ECR discharge initiation.
• This limitation impedes the generation of critical plasma densities required for efficient ECR discharge within the microwave pulse duration.

Purpose of the Study:

• To develop a method for rapidly triggering electron cyclotron resonance (ECR) discharges under low gas pressure conditions in ECRISs.
• To overcome the challenge of prolonged microwave discharge development times at low pressures.
• To reduce microwave power losses by shortening the ECR discharge initiation time.

Main Methods:

• Proposed a novel approach using auxiliary pulsed discharges in crossed ExB fields to pre-fill the magnetic trap with plasma.
• Utilized a glow plasma trigger based on Penning or magnetron discharge.
• Investigated the plasma density and electron temperature achieved by the auxiliary discharge.

Main Results:

• Successfully filled the magnetic trap with plasma at a density of 10^12 cm^-3, sufficient for rapid plasma density increase.
• Achieved initial heating of plasma electrons to approximately 20 eV.
• Demonstrated the capability to initiate ECR discharge ignition more rapidly under low-pressure conditions.

Conclusions:

• The proposed glow plasma trigger effectively pre-conditions the plasma for faster ECR discharge ignition in ECRISs.
• This method allows for operation at lower pressures, facilitating higher ion charge states.
• The technique shows promise for improving the efficiency and performance of ECRIS for advanced physics applications.