Multi-slit triode ion optical system with ballistic beam focusing.

Area of Science:

• Plasma Physics
• Fusion Energy
• Ion Optics

Background:

• Intense focused neutral beams are essential for efficient plasma heating in fusion devices.
• Multi-slit triode ion-optical systems with spherical electrodes offer a promising approach for generating such beams.
• Existing systems require optimization for advanced fusion applications like Tokamak Configuration Variable (TCV).

Purpose of the Study:

• To develop and characterize multi-slit triode ion-optical systems for generating intense focused neutral beams.
• To evaluate the performance of these systems in forming proton and deuterium beams for plasma heating.
• To adapt and optimize ion optical systems for specific fusion devices, such as the TCV.

Main Methods:

• Design and fabrication of two distinct multi-slit triode ion-optical systems with spherical electrodes.
• Experimental generation and analysis of proton beams (15 keV, 140 A, 30 ms).
• Development and testing of a system for the TCV, producing deuterium beams (35 keV, 1 MW, 2 s).

Main Results:

• The first system successfully formed a 15 keV proton beam with 140 A current and 30 ms duration.
• The second system, designed for TCV, generated a focused deuterium neutral beam with 35 keV energy, 1 MW power, and 2 s duration.
• The deuterium beam exhibited low angular divergence: 20-22 mrad across slits and 12 mrad along slits.

Conclusions:

• Multi-slit triode ion-optical systems are effective for producing intense, focused neutral beams for plasma heating.
• The developed systems demonstrate capability for high-energy, high-power neutral beam injection in fusion research.
• Optimized ion optics are critical for achieving desired beam characteristics and efficient plasma heating in devices like TCV.