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Long pulse H- beam extraction with a rf driven ion source on a high power level
1Max-Planck-Institut für Plasmaphysik, EURATOM Association, 85748 Garching, Germany. kraus@ipp.mpg.de
The Review of Scientific Instruments
|March 3, 2010
Summary
IPP Garching tested radio-frequency (rf) driven negative ion sources for the International Thermonuclear Experimental Reactor. High power reduced negative ion production efficiency, while magnetic filters and caesium conditions impacted performance and pulse duration.
Area of Science:
- Plasma physics
- Fusion energy research
- Ion source technology
Background:
- Neutral beam injection is crucial for heating plasma in fusion devices like the International Thermonuclear Experimental Reactor (ITER).
- Radio-frequency (rf) driven negative ion sources are a promising technology for efficient neutral beam injection.
Purpose of the Study:
- To investigate the applicability of rf-driven negative ion sources for ITER's neutral beam injection.
- To optimize source performance for long-pulse operation at high power levels.
Main Methods:
- Improving the experimental setup for long pulses and up to 100 kW rf power.
- Analyzing the impact of magnetic filter fields on plasma density and beam divergence.
- Investigating the role of rf power and caesium conditions on coextracted electrons.
Main Results:
- Negative ion production efficiency decreases at higher rf power.
- Extracted H(-) currents and beam divergence are sensitive to magnetic filter field strength.
- Pulse duration is limited by increased coextracted electrons, influenced by rf power and caesium conditions.
Conclusions:
- Optimizing magnetic filter fields is key to improving H(-) current and beam symmetry.
- Managing rf power and caesium conditions is essential for extending pulse duration by controlling electron coextraction.
- Further development is needed to ensure the reliable operation of these sources for ITER.
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