Open AccessOptimal geometry for neutral-beam-based optical diagnostics in tokamaks
Author(s) -
Robert James Goldston,
Joshua E. Goldston
Publication year - 1995
Language(s) - English
Resource type - Reports
DOI - 10.2172/206580
Subject(s) - tokamak , tangent , beam (structure) , physics , perpendicular , plasma , spectroscopy , atomic physics , optics , plasma diagnostics , energetic neutral atom , resolution (logic) , computational physics , geometry , nuclear physics , mathematics , quantum mechanics , artificial intelligence , computer science
Spatial resolution is an important issue for neutral-beam-based optical diagnostics in tokamak plasmas, such as charge-exchange recombination spectroscopy (measuring T{sub i} and v{sub {phi}}) and motional Stark effect (measuring B{sub p}). The key geometrical constraint is that the optical sightlines of these diagnostics must be as nearly tangent as possible to magnetic surfaces at the point where they cross the path of the neutral beam. This minimizes the effect of the width of the neutral beam on the spatial resolution of the diagnostic in the direction perpendicular to the flux surfaces