Open AccessComparison of Measurement And Modeling Of Current Profile Changes Due To Neutral Bean Ion Redistribution During TAE Avalanches in NSTX
Author(s) -
Douglas Darrow
Publication year - 2013
Language(s) - English
Resource type - Reports
DOI - 10.2172/1087723
Subject(s) - ion , beam (structure) , atomic physics , ion beam , plasma , redistribution (election) , toroid , physics , phase space , distribution function , optics , nuclear physics , politics , political science , law , thermodynamics , quantum mechanics
Brief "avalanches" of toroidal Alfven eigenmodes (TAEs) are observed in NSTX plasmas with several different n numbers simultaneously present. These affect the neutral beam ion distribution as evidenced by a concurrent drop in the neutron rate and, sometimes, beam ion loss. Guiding center orbit modeling has shown that the modes can transiently render portions of the beam ion phase space stochastic. The resulting redistribution of beam ions can also create a broader beam-driven current profile and produce other changes in the beam ion distribution functio