Effect of three-dimensional conducting structures on vertical stability in EAST

Chen, S.L.; Villone, F.; Barbato, L.; Mastrostefano, S.; Xiao, Bingjia; Luo, Z.P.

doi:10.1088/0029-5515/55/1/013010

Cited by 24 publications

(56 citation statements)

References 21 publications

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“…A runaway electron beam can be well constrained in this configuration. This experimental phenomenon has been observed in the HL-2A tokamak [28].…”

Section: Resultssupporting

confidence: 63%

“…The time evolution of the images of fast-ion losses due to long-lived mode (LLM) and sawtooth crashes was also measured during the same discharge, as shown in figure 7. Longlived saturated internal modes, observed on many devices [26][27][28], are thought to originate from the pressure gradient in plasmas with a safety factor profile having either a weakly reversed shear or a broad low-shear region. These modes often cause rotation flattening in the plasma core, and degrade fastion confinement and plasma stored energy.…”

Section: Resultsmentioning

confidence: 99%

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Measurements of fast-ion losses induced by MHD instabilities using a scintillator-based probe in the HL-2A tokamak

Zhang¹,

Liu²,

Chen³

et al. 2015

Nucl. Fusion

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Characteristics of fast-ion losses induced by various magnetohydrodynamic (MHD) instabilities, such as tearing mode (TM), long-lived mode (LLM), and sawtooth crash, have been observed and experimentally investigated in the HL-2A tokamak. To study fastion losses, a new scintillator-based lost-fast ion probe has been developed and used, and an increment of the fast-ion loss rate as the MHD amplitude increase has been measured. Compared with TM and LLM, the fast-ion losses induced by sawtooth crash have a broad range in energy and pitch angle. There may be some interactions between fast ions and magnetic disturbance, which cause the losses with a wide range of energy and pitch angle. During disruptions, the total neutron emission rate drops by ~90% as a result of the strong fast-ion losses. The possible reasons for this phenomenon are the strong magnetic perturbations and the drastic change of the fast-ion transport. In addition, the clear experimental evidence of drastic losses of fast ions during disruptions have been obtained.

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“…A runaway electron beam can be well constrained in this configuration. This experimental phenomenon has been observed in the HL-2A tokamak [28].…”

Section: Resultssupporting

confidence: 63%

Section: Resultsmentioning

confidence: 99%

Measurements of fast-ion losses induced by MHD instabilities using a scintillator-based probe in the HL-2A tokamak

Zhang¹,

Liu²,

Chen³

et al. 2015

Nucl. Fusion

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show abstract

“…The passive plates have been moved inwards, but their thickness has been decreased; the effects of these two changes on vertical stability tend to compensate for each other. Previous analyses in [25] show that the upper divertor structure has a much smaller effect on vertical stability, due to its position and toroidal segmentation. Hence, the overall effect on vertical stability of the changes made in 2014 in plasma facing components is not expected to be dramatic.…”

Section: East Qsf Equilibria Modelling and Optimizationmentioning

confidence: 93%

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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“…The EAST tokamak 4 is a remarkable exception in this respect. Indeed, with reference to the old geometry of EAST (significantly upgraded in 2014) it has been demonstrated 5 that in this device the vessel is too far from the plasma to provide passive stabilization, which is hence guaranteed by plasma facing components. These are intrinsically non-axisymmetric, being toroidally segmented and connected to the vessel through supports.…”

mentioning

confidence: 99%

3D passive stabilization of n = 0 MHD modes in EAST tokamak

Chen

Villone

Xiao

et al. 2016

Sci Rep

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Evidence is shown of the capability of non-axisymmetrical conducting structures in the Experimental Advanced Superconducting Tokamak (EAST) to guarantee the passive stabilization of the n = 0 MHD unstable mode. Suitable numerical modeling of the experiments allows a clear interpretation of the phenomenon. This demonstration and the availability of computational tools able to describe the effect of 3D conductors will have a huge impact on the design of future fusion devices, in which the conducting structures closest to plasma will be highly segmented.

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Effect of three-dimensional conducting structures on vertical stability in EAST

Cited by 24 publications

References 21 publications

Measurements of fast-ion losses induced by MHD instabilities using a scintillator-based probe in the HL-2A tokamak

Measurements of fast-ion losses induced by MHD instabilities using a scintillator-based probe in the HL-2A tokamak

EAST alternative magnetic configurations: modelling and first experiments

3D passive stabilization of n = 0 MHD modes in EAST tokamak

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