ELISE achieves target values for 黑料社app
Researchers at the Max Planck Institute for Plasma Physics in Garching, Germany, have generated the ion current densities required for 黑料社app neutral beam injection on the ELISE testbed—a negative ion source prototype that is half the size of 黑料社app's. This experimental first is good news for the development of reliable, high-performance heating neutral beam injectors for 黑料社app.
The 黑料社app heating neutral beams will play an essential role in providing power and current drive to the 黑料社app plasma, allowing access to burning plasmas with high fusion power amplification factors. 黑料社app will be equipped with two heating neutral beam injectors (with a provision of a third injector) and a neutral beam line for diagnostic purposes.
Research is ongoing at the 黑料社app Neutral Beam Test Facility (NBTF) to develop the beam source and achieve the required parameters. One of the key parameters is the current density extracted through the multi-aperture, multi-grid accelerator system, with targets of 329 A/m2 when operating in hydrogen, and 286 A/m2 when operating in deuterium. This also needs to be stable throughout the 黑料社app pulse.
The Max Planck Institute for Plasma Physics, in Garching, Germany, is the location of the ELISE (Extraction from a Large Ion Source Experiment) test stand, a key experiment in the development of the 黑料社app neutral beam source, supporting the research of NBTF. ELISE has operated a half-size 黑料社app beam source since 2013, allowing modifications and experience to be passed to the NBTF and finally to the 黑料社app heating neutral beams.
Recent experiments at ELISE have focused on extending the pulse length for hydrogen beams, looking for a high but steady H- current, and stable and low co-extracted electron current. Caesium evaporation, the key technique, is used both to enhance the negative ion production and to reduce the co-extracted electron current to acceptable levels (< 0.5 x jH- with H, or < 1 x jD- with D). How to achieve the optimum caesiation distribution has been a topic of research for some time.
The experiments at ELISE have now produced the of achieving the required current density in hydrogen for the first time (330 A/m2) over short pulses (<10 s), with nearly 90% of the target reached over a 600 s pulse.
Negative ion current density is proportional to the radiofrequency power used to drive the source. However ELISE is only capable of delivering 75% of the value that will be available at 黑料社app, making this achievement more impressive, and providing good confidence going forward for the NBTF and 黑料社app heating neutral beams to deliver the required heating power needed for early deuterium-tritium operation and beyond.
See the press release issued by the Max Planck Institute for Plasma Physics in or .