Recent plasma control progress on EAST

Xiao, Bingjia; Yuan, Q.P.; Humphreys, D.A.; Walker, M.L.; Hyatt, A.W.; Leuer, J.A.; Jackson, G.L.; Mueller, D.; Penaflor, B.G.; Pigrowski, D.A.; Johnson, Robert D.; Welander, A.S.; Zhang, R.R.; Luo, Zhi; Guo, Youming; Xing, Zhe; Zhang, Y.

doi:10.1016/j.fusengdes.2012.06.013

Cited by 20 publications

(9 citation statements)

References 8 publications

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“…In these experiments the simplest form of plasma current and position (i.e. plasma centroid) control has been used, the so-called RZIP control [34]. The control parameters are regulated by adjusting the current in the PF coils.…”

Section: Resultsmentioning

confidence: 99%

EAST alternative magnetic configurations: modelling and first experiments

et al. 2015

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Heat and particle loads on the plasma facing components are among the most challenging issues to be solved for a reactor design. Alternative magnetic configurations may enable tokamak operation with a lower peak heat load than a standard single null (SN) divertor. This papers reports on the creation and control of one of such alternatives: a two-null nearby divertor configuration. An important element of this study is that this two-null divertor was produced on a large superconducting tokamak as an experimental advanced superconducting tokamak. A preliminary experiment with the second null forming a configuration with significant distance between the two nulls and a contracting geometry near the target plates was performed in 2014. These configurations have been designed using the FIXFREE code and optimized with CREATE-NL tools and are discussed in the paper. Predictive edge simulations using the TECXY code are also presented by comparing the advanced divertor and SN configuration. Finally, the experimental results of ohmic and low confinement (L-mode) two-null divertor and SN discharges and interpretative two-dimensional edge simulations are discussed. Future experiments will be devoted to varying the distance between the two nulls in high confinement (H-mode) discharges.

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Section: Resultsmentioning

confidence: 99%

EAST alternative magnetic configurations: modelling and first experiments

et al. 2015

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“…The SMBI system, installed about 2 m away from the core plasma at the LFS midplane [18], is now used as the prime radiative feedback actuator with the injection speed reaching about 800 m s −1 . The total time from the moment that the gas-puffing command is sent from the plasma control system (PCS) [20] to the moment that the radiative diagnostic measures a change caused by the impurity gas is less than 8 ms for SMBI, but more than 100 ms for the standard divertor PE valve. The fast response speed of SMBI comes from some comprehensive factors.…”

Section: Actuators Of the Control Systemmentioning

confidence: 99%

Achievement of radiative feedback control for long-pulse operation on EAST

Yuan

Xiao

et al. 2018

Nucl. Fusion

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The active feedback control of radiated power to prevent divertor target plates overheating during long-pulse operation has been developed and implemented on EAST. The radiation control algorithm, with impurity seeding via a supersonic molecular beam injection (SMBI) system, has shown great success in both reliability and stability. By seeding a sequence of short neon (Ne) impurity pulses with the SMBI from the outer mid-plane, the radiated power of the bulk plasma can be well controlled, and the duration of radiative control (feedforward and feedback) is 4.5 s during a discharge of 10 s. Reliable control of the total radiated power of bulk plasma has been successfully achieved in long-pulse upper single null (USN) discharges with a tungsten divertor. The achieved control range of is 20%–30% in L-mode regimes and 18%–36% in H-mode regimes. The temperature of the divertor target plates was maintained at a low level during the radiative control phase. The peak particle flux on the divertor target was decreased by feedforward Ne injection in the L-mode discharges, while the Ne pulses from the SMBI had no influence on the peak particle flux because of the very small injecting volume. It is shown that although the radiated power increased, no serious reduction of plasma-stored energy or confinement was observed during the control phase. The success of the radiation control algorithm and current experiments in radiated power control represents a significant advance for steady-state divertor radiation and heat flux control on EAST for near-future long-pulse operation.

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“…EAST is equipped with 14 superconducting poloidal field (PF) coils (IPF,max=11kA during normal/off-normal operations) for ohmic heating, ohmic current drive, shaping and position control, located outside the toroidal field coils (TFCs). In addition, two 2-turn in-vessel active feedback coils (IC coils), symmetrically located, in the upper and lower part of the vessel and connected in anti-series in order to provide a horizontal field [4], are used for fast control of the plasma vertical instability. Presently, PFC of EAST include ITER-like actively cooled W monoblock upper divertor with up to 10 MWm −2 heat removing capacity [5], a lower divertor in Carbon material and Molybdenum-tiled vacuum vessel.…”

Section: Introductionmentioning

confidence: 99%