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U.S. Department of Energy
Office of Scientific and Technical Information

Suitability of millimeter-wave scattering for diagnostics of fusion alpha-particles

Technical Report ·
OSTI ID:5386691
Collective Thomson scattering using long-pulse, millimeter-wave sources is potentially a powerful diagnostic technique of localized alpha particle velocity distribution and density in a fusion tokamak. The combination of a long-pulse and long-wavelength source optimizes the achievable signal to noise ratio of this diagnostic. Additional advantages of millimeter-waves include large scattering angles up to 180/sup 0/, wide-bandwidth receivers, and suitability of millimeter waveguide techniques in a radiation environment. The Doppler broadened scattered spectrum provides an unambiguous measure of the alpha particle parameters even for a scattering plane orientation near perpendicular to the magnetic field because magnetized particle resonances will be averaged out by finite diagnostic beam divergence and frequency resolution. Millimeter-wave accessibility in tokamaks using x-mode propagation at frequencies between the lower x-mode cutoff and the upper hybrid resonance may be a natural consequence of high field tokamak operation. 45 refs., 8 figs., 1 tab.
Research Organization:
Massachusetts Inst. of Tech., Cambridge (USA). Plasma Fusion Center
DOE Contract Number:
AC02-78ET51013
OSTI ID:
5386691
Report Number(s):
DOE/ET/51013-230; PFC/RR-87-16; ON: DE88006262
Country of Publication:
United States
Language:
English