Skip to main content
Open Access Publications from the University of California

Measurement of the Dαspectrum produced by fast ions in DIII-D

  • Author(s): Luo, Y
  • Heidbrink, WW
  • Burrell, KH
  • Kaplan, DH
  • Gohil, P
  • et al.

Published Web Location Commons Attribution 4.0 International Public License

Fast ions are produced by neutral beam injection and ion cyclotron heating in toroidal magnetic fusion devices. As deuterium fast ions orbit around the device and pass through a neutral beam, some deuterons neutralize and emit Dαlight. For a favorable viewing geometry, the emission is Doppler shifted away from other bright interfering signals. In the 2005 campaign, we built a two channel charge-coupled device based diagnostic to measure the fast-ion velocity distribution and spatial profile under a wide variety of operating conditions. Fast-ion data are acquired with a time resolution of ∼1 ms, spatial resolution of ∼5 cm, and energy resolution of ∼10 keV. Background subtraction and fitting techniques eliminate various contaminants in the spectrum. Neutral particle and neutron diagnostics corroborate the Dαmeasurement. Examples of fast-ion slowing down and pitch angle scattering in quiescent plasma and fast-ion acceleration by high harmonic ion cyclotron heating are presented. © 2007 American Institute of Physics.

Many UC-authored scholarly publications are freely available on this site because of the UC Academic Senate's Open Access Policy. Let us know how this access is important for you.

Main Content
Current View