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February 3–6, 2025
Amelia Island, FL|Omni Amelia Island Resort
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Christmas Night
Twas the night before Christmas when all through the houseNo electrons were flowing through even my mouse.
All devices were plugged in by the chimney with careWith the hope that St. Nikola Tesla would share.
S. C. Chiu, V. S. Chan
Fusion Science and Technology | Volume 18 | Number 4 | December 1990 | Pages 591-596
Alpha Particles in Fusion Research | doi.org/10.13182/FST90-A29251
Articles are hosted by Taylor and Francis Online.
Fast-wave current drive presents a promising scheme for steady-state operation of reactor tokamaks. This scheme is being studied for application in the International Thermonuclear Experimental Reactor (ITER), the Joint European Torus (JET), and the Doublet III-D reactor (DIII-D). There are two regimes that appear to be promising, the low-frequency range 0 < ω < 2ΩD and the lower hybrid frequency range ΩD ≪ ω < ωLH. In the latter scheme, the wavelength of the fast wave becomes much shorter than the alpha-particle gyroradius and alpha-particle absorption can become significant. An analytic formula for alpha-particle absorption of fast waves for the standard slowing down distribution has been derived and compared with electron absorption at ITER parameters. It has been found that at TD > 30 keV and ne ∼ 1014 cm−3, the alpha-particle absorption is large and can greatly decrease the current drive efficiency. However, without sacrificing the fusion reactivity rate, by increasing the density and decreasing the temperature 15 keV < TD < 25 keV, the alpha-particle absorption can become small at a sufficiently high frequency. It is suggested that a simulation of the alpha-particle absorption effect on fast-wave current drive can be made in DIII-D by using a lower frequency source (∼30 MHz) to create a minority tail and a high-frequency source (200 MHz) to drive the current. Results of minority absorption are presented. Effects that can improve current drive efficiency are discussed.