Contemporary Instrumentation and Application of Charge Exchange Neutral Particle Diagnostics in Magnetic Fusion Experiments

An overview of the developments post-circa 1980's of the instrumentation and application of charge exchange neutral particle diagnostics on Magnetic Fusion Energy experiments is presented

Conceptual design of pellet charge eXchange (PCX) diagnostics for stellarator W7-X

Pellet Charge eXchange diagnostic using Li pellets has been considered for the W7-X machine. Geometry of the experimental set-up and parameters of both lithium pellet injector (LPI) and neutral particle analyser (NPA) were evaluated. It was shown that this diagnostics can provide very well detectable H"0 signal in the range 50 - 1000 keV generated by RF driven H"+ minority ions in W7-X. The PCX diagnostics will be able to measure H"+ energy spectra and density profiles in wide range of W7-X plasma parameters. The proposed NPA can be designed on a basis of the NPA ISEP (Ioffe institute) installed now on JET. A pellet light-gas gun can be used to accelerate Li pellets of 2 - 3 mm in size up to 1 km/s velocities. That provides the required pellet penetration into the plasma core. Due to sticky problems with Li operation, a special technique of loading and keeping the pellets in a charger unit of LPI has to be developed. Development of PCX diagnostics for absolute measurements of the confined minority protons requires improvement of the pellet ablation model used. Knowledge of the cloud dimensions and density distributions of different charge states of ions is of special interest. It is necessary to improve predictions of pellet penetrations in non-Maxwellian plasmas as well. An optical system for measurements of pellet cloud density profiles should be foreseen on W7-X. (orig.)Available from TIB Hannover: RA 71(10/20) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman