A Code that Simulates Fast-Ion Dα and Neutral Particle Measurements
Open Access
- 1 September 2011
- journal article
- Published by Global Science Press in Communications in Computational Physics
- Vol. 10 (3), 716-741
- https://doi.org/10.4208/cicp.190810.080211a
Abstract
A code that models signals produced by charge-exchange reactions between fast ions and injected neutral beams in tokamak plasmas is described. With the fast-ion distribution function as input, the code predicts the efflux to a neutral particle analyzer (NPA) diagnostic and the photon radiance of Balmer-alpha light to a fast-ion Dα (FIDA) diagnostic. Reactions with both the primary injected neutrals and with the cloud of secondary “halo” neutrals that surround the beam are treated. Accurate calculation of the fraction of neutrals that occupy excited atomic states (the collisional-radiative transition equations) is an important element of the code. Comparison with TRANSP output and other tests verify the solutions. Judicious selection of grid size and other parameters facilitate efficient solutions. The output of the code has been validated by FIDA measurements on DIII-D but further tests are warranted.Keywords
This publication has 25 references indexed in Scilit:
- Active and passive spectroscopic imaging in the DIII-D tokamakPlasma Physics and Controlled Fusion, 2010
- Profiles of fast ions that are accelerated by high harmonic fast waves in the National Spherical Torus ExperimentPlasma Physics and Controlled Fusion, 2010
- Beam-ion confinement for different injection geometriesPlasma Physics and Controlled Fusion, 2009
- Measurements of fast-ion acceleration at cyclotron harmonics using Balmer-alpha spectroscopyPlasma Physics and Controlled Fusion, 2007
- The tokamak Monte Carlo fast ion module NUBEAM in the National Transport Code Collaboration libraryComputer Physics Communications, 2004
- Principles of Plasma Diagnostics: Second EditionPlasma Physics and Controlled Fusion, 2002
- Excited-state populations in neutral beam emissionPlasma Physics and Controlled Fusion, 2001
- Effects of edge plasma turbulence on radial correlation length measurements with BESReview of Scientific Instruments, 1992
- Penetration of energetic neutral beams into fusion plasmasNuclear Fusion, 1989
- Semi-empirical cross sections for excitation of hydrogen atoms by protonsJournal of Physics B: Atomic and Molecular Physics, 1976