Magnetic perturbation effects on boundary plasmas during high power lower hybrid current drive in Tore Supra

Evans, T.E.; Goniche, M.; Grosman, A.; Guilhem, D.; Hess, W.; Vallet, J.C.

doi:10.1016/s0022-3115(06)80071-1

Cited by 48 publications

(50 citation statements)

References 1 publication

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“…3 Since the first RMPs experiment on PULSATOR, 4 many experiments related to RMPs have been carried out. 1,[4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] The RMPs related experiments covers a broad spectrum of physics issues including the effect of RMPs on tearing mode (TM) dynamics, 1, 4-10 error field, 11,12 particle transport, 13,14 and mitigation or suppression of edge localized modes (ELMs).…”

Section: Introductionmentioning

confidence: 99%

Understanding the effect of resonant magnetic perturbations on tearing mode dynamics

Ren

et al. 2013

Physics of Plasmas

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Abstract. Numerical understandings of the effect of resonant magnetic perturbations (RMPs) on 2/1 tearing mode (TM) dynamics observed on J-TEXT tokamak (Hu Q. et al 2012 Nucl. Fusion 52 083011) are presented in this paper. The non-uniform mode rotation frequency, modulated by electromagnetic force (F em ) and viscous force (F vs ), results in the applied RMPs contributing both net stabilizing and braking effect on TM. Numerical evaluation based on analytical theory shows the applied RMP contributes a dominant stabilizing effect, which are responsible for the suppression of TM. The dynamics of the first discovered small locked island (SLI) are investigated. It is found that the island is locked at the stabilizing phase and the saturated island width is less than the linear layer width. The simulated Mirnov signal indicates the small locked island is likely to be the complete suppression case observed in experiments. Associated with the application of RMP, the shape of Mirnov signal deviates from sinusoidal before mode locking, which is explained by numerical modeling. The comparisons between the numerical and experimental results are in good agreement phenomenally.

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Section: Introductionmentioning

confidence: 99%

Understanding the effect of resonant magnetic perturbations on tearing mode dynamics

Ren

et al. 2013

Physics of Plasmas

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“…Such resonances create a zone of chaotic magnetic field lines at the plasma edge that controls stability or transport of heat and particles therein. Such external resonant perturbations can be produced by ergodic limiters, [10][11][12][13] that have been shown to improve plasma confinement, 14 as well as to control magnetic activity 15 and plasma disruptions. [16][17][18][19] Furthermore, a recent experiment has shown that ergodic divertors can also be successfully applied to mitigate edge localized modes while maintaining the plasma confinement.…”

Section: Introductionmentioning

confidence: 99%

Escape patterns of chaotic magnetic field lines in a tokamak with reversed magnetic shear and an ergodic limiter

et al. 2008

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Escape patterns of chaotic magnetic field lines in a tokamak with reversed magnetic shear and an ergodic limiter PHYSICS OF PLASMAS, v.15, n.9, 2008 http://producao.usp.br/handle/BDPI/15972 The existence of a reversed magnetic shear in tokamaks improves the plasma confinement through the formation of internal transport barriers that reduce radial particle and heat transport. However, the transport poloidal profile is much influenced by the presence of chaotic magnetic field lines at the plasma edge caused by external perturbations. Contrary to many expectations, it has been observed that such a chaotic region does not uniformize heat and particle deposition on the inner tokamak wall. The deposition is characterized instead by structured patterns called magnetic footprints, here investigated for a nonmonotonic analytical plasma equilibrium perturbed by an ergodic limiter. The magnetic footprints appear due to the underlying mathematical skeleton of chaotic magnetic field lines determined by the manifold tangles. For the investigated edge safety factor ranges, these effects on the wall are associated with the field line stickiness and escape channels due to internal island chains near the flux surfaces. Comparisons between magnetic footprints and escape basins from different equilibrium and ergodic limiter characteristic parameters show that highly concentrated magnetic footprints can be avoided by properly choosing these parameters.

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“…7 Furthermore, several experiments in tokamaks show that, under special conditions, the edge particle transport can be influenced by the magnetic oscillations. Thus, experiments performed with ergodic divertors in Texas Experimental Tokamak ͑TEXT͒, 8 Tore Supra, 9,10 Torus Experiment for Technology Oriented Research ͑TEXTOR͒, 11 Hybtok-II, 12 and DIII-D 13 demonstrated that an ergodized magnetic boundary can influence parameter profiles and reduce the transport. Beside this experimental evidence, some theoretical works also predict a possible influence of magnetic fluctuations on the collisional drift-wave turbulence in tokamaks.…”

Section: Introductionmentioning

confidence: 99%

Electrostatic turbulence driven by high magnetohydrodynamic activity in Tokamak Chauffage Alfvén Brésilien

et al. 2008

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In Tokamak Chauffage Alfvén Brésilien [R. M. O. Galvão et al., Plasma Phys. Controlled Fusion 43, 1181 (2001)], high magnetohydrodynamic (MHD) activity may appear spontaneously or during discharges with a voltage biased electrode inserted at the plasma edge. The turbulent electrostatic fluctuations, measured by Langmuir probes, are modulated by Mirnov oscillations presenting a dominant peak with a common frequency around 10kHz. We report the occurrence of phase locking of the turbulent potential fluctuations driven by MHD activity at this frequency. Using wavelet cross-spectral analysis, we characterized the phase and frequency synchronization in the plasma edge region. We introduced an order parameter to characterize the radial dependence of the phase-locking intensity.

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Magnetic perturbation effects on boundary plasmas during high power lower hybrid current drive in Tore Supra

Cited by 48 publications

References 1 publication

Understanding the effect of resonant magnetic perturbations on tearing mode dynamics

Understanding the effect of resonant magnetic perturbations on tearing mode dynamics

Escape patterns of chaotic magnetic field lines in a tokamak with reversed magnetic shear and an ergodic limiter

Electrostatic turbulence driven by high magnetohydrodynamic activity in Tokamak Chauffage Alfvén Brésilien

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