Charge Exchange Recombination Spectroscopy Optimisation with the TCV Diagnostic Neutral Beam
A Diagnostic Neutral Beam Injector (50kV extraction voltage, 0.8A effective current) has been installed on the TCV Tokamak for ion temperature and impurity density profile measurements. Initial measurements of visible carbon CVI(n= 8 ?7) transition at lambda=5291 A showed that the DNBI signal is only 25% of the measured signal at an average plasma density of 1-2.10(19)m(-3) and ~5% at 5.10(19)m(-3). The passive plasma emissivity profile, measured by inverting a vertical multi-chord view of the plasma, was highly peaked at the plasma edge corresponding to a thermal hydrogen neutral density of ~10(-4)-10(-5).ne. A model used to calculate the DNBI and background emissivity along the diagnostic lines of sight show that in order to obtain an ion temperature measurement from the DNBI, the collection efficiency of the optical system must be increased to improve the photon statistics and the DNBI neutral density in the observation region must be increased by a factor of 3-10.
Bibliographic Reference: An oral report given at: The 28th EPS Conference of Controlled Fusion and Plasma Physics. Held in: Madeira (PT) June 2001
Record Number: 200013691 / Last updated on: 2001-09-18
Original language: en
Available languages: en