A. Kirk I.T. Chapman J. Harrison Yueqiang Liu E. Nardon S. Saarelma R. Scannell A.J. Thornton The Mast Team
The application of resonant magnetic perturbations (RMPs) with a toroidal mode number of n=4 or n=6 to lower single null plasmas in the MAST tokamak produces up to a factor of 5 increase in Edge Localized Mode (ELM) frequency and reduction in plasma energy loss associated with type-I ELMs. A threshold current for ELM mitigation is observed above wh…
PublishedC.J. Ham Y.Q. Liu J.W. Connor S.C. Cowley R.J. Hastie T.C. Hender T.J. Martin
Two methods for calculating tearing mode stability are described in this paper. A fast method using the recently improved T7 code (Ham et al. 2012 Plasma Phys. Control. Fusion 54 025009) and a new method based on the MARS-F MHD stability code (Liu et al. 2000 Phys. Plasmas 7 3681) which constructs the tearing mode solution from calculated basis fun…
PublishedA. Kirk J. Harrison Yueqiang Liu E. Nardon I. T. Chapman P. Denner The Mast Team
The application of nonaxisymmetric resonant magnetic perturbations (RMPs) with a toroidal mode number n . 6 in the MAST tokamak produces a significant reduction in plasma energy loss associated with type-I edge localized modes (ELMs), the first such observation with n>3 . During the ELM mitigated stage clear lobe structures are observed in visible-…
PublishedZ. R. Wang S. C. Guo Y. Q. Liu
The physics of kinetic effects on the resistive wall mode (RWM) stability is studied, and a comparison between reversed field pinch (RFP) and Tokamak configurations is made. The toroidal, magnetohydrodynamic (MHD)-kinetic hybrid stability code MARS-K, in which the drift kinetic effects are self-consistently incorporated into the MHD formulation, is…
PublishedYueqiang Liu J. W. Connor S. C. Cowley C. J. Ham R. J. Hastie et al.
Within the single fluid theory for a toroidal, resistive plasma, the favorable average curvature effect [Glasser et al. , Phys. Fluids 18 , 875 (1975)], which is responsible for the strong stabilization of the classical tearing mode at finite pressure, can also introduce a strong screening effect to the externally applied resonant magnetic field. C…
PublishedR. J. Buttery A. H. Boozer Y. Q. Liu J.-K. Park N. M. Ferraro
Significant progress has been made in interpreting the effects of non-axisymmetric “error” fields on a plasma through ideal MHD stability and a dominant “least stable” ideal mode through which the fields couple to the tearing resonant surface. However, in contrast to expectations from such theories, experiments have found limited success in…
PublishedLi Li Yue Liu Yueqiang Liu
An analytic model of non-linear feedback stabilization of the resistive wall mode is presented. The non-linearity comes from either the current or the voltage saturation of the control coil power supply. For the so-called flux-to-current control, the current saturation of active coils always results in the loss of control. On the contrary, the flux…
PublishedPui-Wai Ma W. C. Liu C. H. Woo S. L. Dudarev
We perform large-scale molecular dynamics simulations to study the magnetic properties of amorphous iron under pressure. Simulations, exceeding by at least two orders of magnitude those accessible to density functional calculations, use the recently developed magnetic interatomic potential for iron. The distributions of the size of atomic magnetic …
PublishedG.Z. Hao Y.Q. Liu A.K. Wang H.B. Jiang Gaimin Lu H.D. He X.M. Qiu
A theoretical model for investigating the effect of the trapped energetic particles EPs on the resistive wall mode RWM instability is proposed. The results demonstrate that the trapped EPs have a dramatic stabilizing effect on the RWM because of resonant interaction between the mode and the magnetic precession drift motion of the trapped EPs. The r…
Published