Plasma and Fusion Research
Volume 2, S1111 (2007)
Regular Articles
- Japan Atomic Energy Agency, Naka, Ibaraki 311-0193, Japan
Abstract
A collective Thomson scattering (CTS) diagnostic using carbon dioxide (CO2) laser is being developed to establish a diagnostic method of confined α-particles in burning plasmas. To realize the CTS diagnostic, a transversely excited atmospheric CO2 laser has been developed. To obtain single-mode output, which is needed for the CTS diagnostic, seed laser is injected to the cavity with an unstable resonator. Using this technique, output energy of 17 J at a repetition rate of 15 Hz has been achieved. This result gives a prospect for the CTS diagnostic on International Thermonuclear Experimental Reactor (ITER). Proof-of-principle test of the CTS diagnostic is being performed with the new laser system on JT-60U. A method to improve spatial and spectral resolutions, which is subject to be resolved for the CO2 laser CTS, is proposed using a resonance at the lower hybrid frequency. Calculation results show that the scattering power increases more than a factor of 10, and spatial and spectral resolution improve about 30% if the scattered wave vector is nearly perpendicular to the magnetic field.
Keywords
collective Thomson scattering, burning plasma, carbon-dioxide laser, international thermonuclear experimental reactor, JT-60U
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This paper may be cited as follows:
Takashi KONDOH, Toshimitsu HAYASHI, Yasunori KAWANO, Yoshinori KUSAMA and Tatsuo SUGIE, Plasma Fusion Res. 2, S1111 (2007).