Development of a novel surface assisted volume negative hydrogen ion source.

Area of Science:

• Plasma Physics
• Fusion Energy Technology
• Materials Science

Background:

• Negative hydrogen ions (H-) are crucial for neutral beam injectors in fusion reactors.
• Current H- ion source designs face challenges in production efficiency, extraction, and cesium management.

Purpose of the Study:

• To investigate a novel surface-assisted volume H- ion production method.
• To overcome limitations of existing H- ion source technologies.

Main Methods:

• A proof-of-principle experiment was conducted using cesium-coated tungsten dust sprinkled into hydrogen plasma.
• Four diagnostics were employed: Langmuir probe, ion acoustic wave phase velocity, dust current, and Balmer line ratio.

Main Results:

• The H- ion fraction was measured to be between approximately 0.2 and 0.3 with respect to plasma density.
• Results were obtained under various discharge conditions in the presence of cesium-coated tungsten dust.
• Experimental findings showed good agreement with theoretical estimations.

Conclusions:

• The novel method of surface-assisted volume H- ion production using Cs-coated W dust is validated.
• This approach offers a promising alternative for improving H- ion generation in fusion reactor applications.