Calculations of two-fluid magnetohydrodynamic axisymmetric steady-states

Ferraro, N.M.; Jardin, S.C.

doi:10.1016/j.jcp.2009.07.015

Cited by 71 publications

(57 citation statements)

References 34 publications

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“…These fields are then Fourier analyzed toroidally and the n = 2 component extractedreferred to as the 'vacuum' n = 2 fields. The vacuum fields together with the axisymmetric EFIT [16] calculated magnetic equilibrium and profiles of density, temperature, impurity density, and rotation are used as inputs to the M3D-C1 code [11][12][13]. M3D-C1 is a resistive two-fluid code which calculates the zero-frequency linear plasma response to the applied 3D fields including perturbed magnetic field, pressure, and density.…”

Section: Description Of Modelmentioning

confidence: 99%

Modulation of prompt fast-ion loss by appliedn= 2 fields in the DIII-D tokamak

Zeeland¹,

Ferraro²,

Heidbrink³

et al. 2013

Plasma Phys. Control. Fusion

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Energy and pitch angle resolved measurements of escaping neutral beam ions (E ≈ 80 keV) have been made during DIII-D L-mode discharges with applied, slowly rotating, n = 2 magnetic perturbations. Data from separate scintillator detectors (FILDs) near and well below the plasma midplane show fast-ion losses correlated with the internal coil (I-coil) fields. The dominant fast-ion loss signals are observed to decay within one poloidal transit time after beam turn-off indicating they are primarily prompt loss orbits. Also, during application of the rotating I-coil fields, outboard midplane edge density and bremsstrahlung emission profiles exhibit a radial displacement of up to δR ≈ 1 cm. Beam deposition and full orbit modeling of these losses using M3D-C1 calculations of the perturbed kinetic profiles and fields reproduce many features of the measured losses. In particular, the predicted phase of the modulated loss signal with respect to the I-coil currents is in close agreement with FILD measurements as is the relative amplitudes of the modulated losses for the co and counter-current beam used in the experiment. These simulations show modifications to the beam ion birth profile and subsequent prompt loss due to changes in the edge density; however, the dominant factor causing modulation of the losses to the fast-ion loss detectors is the perturbed magnetic field (δB/B ≈ 10 −3 in the plasma). Calculations indicate total prompt loss to the DIII-D wall can increase with application of the n = 2 perturbation by up to 7% for co-current injected beams and 3% for counter-current injected beams depending on phase of the perturbation relative to the injected beam.

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Section: Description Of Modelmentioning

confidence: 99%

Modulation of prompt fast-ion loss by appliedn= 2 fields in the DIII-D tokamak

Zeeland¹,

Ferraro²,

Heidbrink³

et al. 2013

Plasma Phys. Control. Fusion

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“…Ref. [6]). The effects encompassed by extended-MHD are variable: extended-MHD refers to models beyond resistive MHD that include some combination of anisotropic thermal conduction and stresses [7], two-fluid evolution [8], finite-Larmorradius closures [9,10], and/or advanced drift-kineticequation closures [11].…”

Section: Introductionmentioning

confidence: 99%

Effect of scrape-off-layer current on reconstructed tokamak equilibrium

et al. 2017

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Methods are described that extend fields from reconstructed equilibria to include scrape-off-layer current through extrapolated parametrized and experimental fits. The extrapolation includes both the effects of the toroidal-field and pressure gradients which produce scrape-off-layer current after recomputation of the Grad-Shafranov solution. To quantify the degree that inclusion of scrapeoff-layer current modifies the equilibrium, the χ-squared goodness-of-fit parameter is calculated for cases with and without scrape-off-layer current. The change in χ-squared is found to be minor when scrape-off-layer current is included however flux surfaces are shifted by up to 3 cm. The impact on edge modes of these scrape-off-layer modifications is also found to be small and the importance of these methods to nonlinear computation is discussed. Published version: Phys. Plasmas 24, 012504 (2017) [http://dx

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“…The equilibrium reconstruction used as input for the resis tive one and twofluid M3DC 1 calculations [30][31][32] was computed with the EFIT code [33] and included the effects of kinetic profiles. The vacuum n = 3 MP fields were obtained from a Biot-Savart calculation for the currents in the MP coils in NSTX.…”

Section: Simulationsmentioning

confidence: 99%

Mitigation of Alfvénic activity by 3D magnetic perturbations on NSTX

Kramer

Bortolon

Ferraro

et al. 2016

Plasma Phys. Control. Fusion

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Observations on the National Spherical Torus Experiment (NSTX) indicate that externally applied nonaxisymmetric magnetic perturbations (MP) can reduce the amplitude of toroidal Alfvén eigenmodes (TAE) and global Alfvén eigenmodes (GAE) in response to pulsed n = 3 nonresonant fields. From fullorbit following Monte Carlo simulations with the one and twofluid resistive MHD plasma response to the magnetic perturbation included, it was found that in response to MP pulses the fastion losses increased and the fastion drive for the GAEs was reduced. The MP did not affect the fastion drive for the TAEs significantly but the Alfvén continuum at the plasma edge was found to be altered due to the toroidal symmetry breaking which leads to coupling of different toroidal harmonics. The TAE gap was reduced at the edge creating enhanced continuum damping of the global TAEs, which is consistent with the observations. The results suggest that optimized nonaxisymmetric MP might be exploited to control and mitigate Alfvén instabilities by tailoring the fastion distribution function and/or continuum structure.

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Calculations of two-fluid magnetohydrodynamic axisymmetric steady-states

Cited by 71 publications

References 34 publications

Modulation of prompt fast-ion loss by appliedn= 2 fields in the DIII-D tokamak

Modulation of prompt fast-ion loss by appliedn= 2 fields in the DIII-D tokamak

Effect of scrape-off-layer current on reconstructed tokamak equilibrium

Mitigation of Alfvénic activity by 3D magnetic perturbations on NSTX

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