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

UC Irvine

UC Irvine Previously Published Works bannerUC Irvine

Hydrogenic fast-ion diagnostic using Balmer-alpha light

  • Author(s): Heidbrink, WW
  • Burrell, KH
  • Luo, Y
  • Pablant, NA
  • Ruskov, E
  • et al.

Hydrogenic fast-ion populations are common in toroidal magnetic fusion devices, especially in devices with neutral beam injection. As the fast ions orbit around the device and pass through a neutral beam, some fast ions neutralize and emit Balmer-alpha light. The intensity of this emission is weak compared with the signals from the injected neutrals, the warm (halo) neutrals and the cold edge neutrals, but, for a favourable viewing geometry, the emission is Doppler shifted away from these bright interfering signals. Signals from fast ions are detected in the DIII-D tokamak. When the electron density exceeds ̃7 × 1019 m-3, visible bremsstrahlung obscures the fast-ion signal. The intrinsic spatial resolution of the diagnostic is ̃5cm for 40keV amu-1 fast ions. The technique is well suited for diagnosis of fast-ion populations in devices with fast-ion energies (̃30 keV amu-1), minor radii (̃0.6 m) and plasma densities (≲ 1020 m-3) that are similar to those of DIII-D.

Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Let us know how this access is important for you.

Main Content
Current View