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-particle diagnostics by CO
laser collective Thomson scattering in ITERKondoh, Takashi; Richards, R. K.*; Hutchinson, D. P.*; Sugie, Tatsuo; Costley, A. E.*; Miura, Yukitoshi; Lee, S.*
Proceedings of 30th EPS Conference on Controlled Fusion and Plasma Physics (CD-ROM), 4 Pages, 2003/07
In order to understand the behavior of alpha-particles which are the dominant heat source in a burning plasma, it is necessary to measure the spatial distribution of the number of the alpha-particles and their energy spectrum. A collective Thomson scattering (CTS) system based on a pulsed CO laser is being developed and is under consideration for alpha-particle measurements on ITER. Heating beam ions (E = 1 MeV) are normally co-injected and have a similar velocity with alpha-particles in ITER. The CTS measurement can not, in general, distinguish beam ions and alpha-particles which have the same velocity. A vertical scattering geometry to distinguish between beam ions and alpha-particles is proposed. Calculations have shown that the vertically viewing CTS can resolve counter-travelling alphas without being masked by beam ions. Preliminary design of a beam line and a receiver system with the vertical scattering geometry has been developed. A proof-of-principle test on the CTS system using the JT-60U plasma is being conducted.
Kondoh, Takashi; Kawano, Yasunori; Costley, A. E.*; Malaquias, A.*; Sugie, Tatsuo; Walker, C.*
Proceedings of 30th EPS Conference on Controlled Fusion and Plasma Physics (CD-ROM), 4 Pages, 2003/07
In order to measure line average electron density for long pulse operation on ITER, a CO laser interferometer/polarimeter system has being selected. High reliability is necessary because the measurements will be used as a reference signal for real time control of the density during long plasma pulses. The design of the interferometer/polarimeter is improved from the previous design because of an input from experiences gained on JT-60U. A dual CO laser interferometer/polarimeter was chosen in order to improve reliability. The proof-of-principle test of the dual CO laser interferometer/polarimeter has been demonstrated and the system is operating routinely on JT-60U. Five tangential sight lines are designed near the midplane of ITER. The laser beams will be transmitted to the plasma through shielding labyrinths in an equatorial port and reflected by retroreflectors. Position of the laser beams will be remotely controlled by steering mirrors outside the port plug because the vacuum vessel of ITER will move due to change in temperature during long plasma pulses.
laser systemKondoh, Takashi; Lee, S.; Miura, Yukitoshi
Purazuma, Kaku Yugo Gakkai-Shi, 76(9), p.883 - 887, 2000/09
no abstracts in English
