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Deuterium results at the negative ion source test facility ELISE
W Kraus1, D Wünderlich1, U Fantz1
1Max-Planck-Institut für Plasmaphysik, Garching, Germany.
The Review of Scientific Instruments
|June 6, 2018
Summary
Researchers improved radio frequency (RF) driven negative ion sources for the ITER fusion project. Optimized caesium procedures reduced electron currents, achieving 66% of the required deuterium ion beam performance for fusion energy.
Area of Science:
- Plasma physics
- Fusion energy research
- Ion source technology
Background:
- ITER requires large radio frequency (RF) driven negative ion sources for neutral beam injection.
- A half-sized source has been operational since 2013 to test ITER requirements.
- High operational reliability and specific beam properties are crucial for ITER.
Purpose of the Study:
- Demonstrate high operational reliability of large negative ion sources.
- Achieve extracted current densities and beam properties for ITER.
- Address performance limitations in long pulses.
Main Methods:
- Technical improvements to the source design and RF system for steady-state operation.
- Optimized caesium evaporation and distribution procedures.
- Reduction and symmetrization of co-extracted electron currents.
Main Results:
- Achieved reliable steady-state operation with RF power up to 300 kW.
- Reached required D- current density in short pulses.
- Extracted 190 A/m² D- for 45 min (66% of ITER requirement) by controlling electron currents.
Conclusions:
- Refined caesium procedures and electron current control are key to improving long-pulse performance.
- Significant progress made towards ITER's negative ion beam requirements.
- Further optimization needed to meet full ITER specifications.
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