Survey of heating and current drive for K-DEMO

Abstract

We present calculations of heating and current drive by neutral injection and by electromagnetic waves in the ion cyclotron, helicon, lower hybrid, and electron cyclotron frequency ranges for the steady state burn conditions in a K-DEMO configuration with I p = 12.3 MA, a = 2.1 m, R o = 6.8 m, B o = 7.4 T, n e = 1.1 × 10 20 m −3 , T(0) = 40 keV, and Z eff = 1.5. Lower hybrid wave current drive calculations comprise a 2D scan over poloidal launcher location and launched n , at a fixed frequency of 5 GHz. An ICRF frequency scan over 50-100 MHz is based on an ITER-like ICRF midplane antenna; the absorption calculation includes thermal D, T, He, Ar, and W as well as suprathermal beam ions and alphas. Helicon fast wave performance is surveyed by varying frequency over 0.6-2.5 GHz, launched n from −1.6 to −3, and launcher position from top to bottom on the low-field side. An ITER-like 1 MeV neutral beam system with quasi-tangential geometry is scanned over elevation to vary the targeted minor radius. The electron cyclotron survey varies the frequency (190-300 GHz), launcher poloidal location, and the poloidal and toroidal direction of the launched waves. We report for each system the range of minor radius in which current is driven, the current drive efficiency, the optimal system parameters, and typical profiles of driven current. Electron and ion heating profiles are reported for the ICRF and NBI systems.

EMC3-EIRENE modeling of edge plasma to improve the ICRF coupling with local gas puffing in DEMO

“…EU-DEMO and K-DEMO is summarized in [2,3] respectively. Among the heating methods, plasma heating with radio-frequency waves in the ion cyclotron range of frequencies (ICRF) is one of the standard heating methods widely used in present tokamaks, stellarators and linear devices.…”

“…DEMO is considered as the final step towards commercial fusion reactor following ITER. The DEMO design used in the paper is the 2015 baseline EU-DEMO design with the following main tokamak parameters: R = 9.07 m, r = 2.93 m, = 1.59, = 0.33, plasma volume = 2502 m 3 , I p = 19.6 MA, B 0 = 5.667 T, q 95 = 3.247, ̅ = 7.98×10 19 m -3 , Z eff = 2.584, H-factor = 1.1, heating power = 300 MW, P sep = 150 MW, net electric power = 500MW, burn time = 2 hours.…”

“…To heat plasma to burning plasma temperature and to maintain this temperature in DEMO, robust auxiliary heating is necessary. Recent progress of heating and current drive for EU-DEMO and K-DEMO is summarized in [2] and [3], respectively. Among the heating methods, plasma heating with radiofrequency waves in the Ion Cyclotron Range of Frequencies (ICRF) is one of the standard heating methods widely used in present tokamaks, stellarators and linear devices.…”

Neutral beam injection for fusion reactors: technological constraints versus functional requirements

“…NBI is also considered for DEMO and fusion power plant (FPP) class devices (see e.g. references [3,4]). Besides plasma heating for ramp-up and burn control, NBI can provide additional functions such as current drive and inducing plasma rotation [5][6][7].…”

“…Besides plasma heating for ramp-up and burn control, NBI can provide additional functions such as current drive and inducing plasma rotation [5][6][7]. While ECRH has the unique property that it can drive current locally with surgical precision and is therefore the actuator of choice for NTM control and precise control of the current profile, NBI is able to provide good current drive efficiency at any radius [4]. NBI is therefore considered one of the preferred systems to provide the non-inductive and non-bootstrap fraction of the plasma current * Author to whom any correspondence should be addressed.…”