Reactor similarity for plasma-material interactions in scaled-down tokamaks as the basis for the Vulcan conceptual design

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• 作者：D.G. Whyte ; ^{whyte@psfc.mit.edu} ; G.M. Olynyk ; H.S. Barnard ; P.T. Bonoli ; L. Bromberg ; M.L. Garrett ; C.B. Haakonsen ; Z.S. Hartwig ; R.T. Mumgaard ; Y.A. Podpaly
• 关键词：28.52  ; .  ; &minus ;   ; s ; 28.52.Fa ; 52.40.Hf ; 52.55.Fa ; 52.55.Rk
• 刊名：Fusion Engineering and Design
• 出版年：2012
• 期刊代码：22_09203796
• 类别：pw
• 出版时间：March, 2012
• 卷：87
• 期：3
• 页码：234-247
• 文件大小：879 K

摘要

Dimensionless parameter scaling techniques are a powerful tool in the study of complex physical systems, especially in tokamak fusion experiments where the cost of full-size devices is high. It is proposed that dimensionless similarity be used to study in a small-scale device the coupled issues of the scrape-off layer (SOL) plasma, plasma-material interactions (PMI), and the plasma-facing material (PFM) response expected in a tokamak fusion reactor. Complete similarity is not possible in a reduced-size device. In addition, 鈥渉ard鈥?technological limits on the achievable magnetic field and peak heat flux, as well as the necessity to produce non-inductive scenarios, must be taken into account. A practical approach is advocated, in which the most important dimensionless parameters are matched to a reactor in the reduced-size device, while relaxing those parameters which are far from a threshold in behavior. 鈥淗ard鈥?technological limits are avoided, so that the reduced-size device is technologically feasible. A criticism on these grounds is offered of the 鈥?em>P/R鈥?model, in which the ratio of power crossing the last closed flux surface (LCFS), P, to the device major radius, R, is held constant. A new set of scaling rules, referred to as the 鈥?em>P/S鈥?scaling (where S is the LCFS area) or the 鈥淧MI鈥?scaling, is proposed: (i) non-inductive, steady-state operation; (ii) P is scaled with R² so that LCFS areal power flux P/S is constant; (iii) magnetic field B constant; (iv) geometry (elongation, safety factor q_*, etc.) constant; (v) volume-averaged core density scaled as ; and (vi) ambient wall material temperature T_W, 0 constant. It is shown that these scaling rules provide fidelity to reactor conditions in the divertor of the reduced-size device, allowing for reliable extrapolation of the behavior of the coupled SOL/PMI/PFM system from the reduced-size device to a reactor. The P/S scaling is used as the basis for the Vulcan tokamak conceptual design.