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UKAEA-CCFE-PR(22)862022
Doppler reflectometry, or the Doppler backscattering (DBS) diagnostic, enables the measurement of turbulent density fluctuations of intermediate length scales, typically $10 gtrsim k_perp rho_i gtrsim 1$; here $k_perp$ is the turbulence’s wavenumber and $rho_i$ is the ion gyroradius. The backscattered power is proportional to the power of the tur…
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2011
A detailed experiment-theory comparison reveals that linear ideal MHD theory is in quantitative agreement with external magnetic and internal soft x-ray measurements of the plasma response to externally applied non-axisymmetric fields over a broad range of beta and rotation. This result represents a significant step toward the goal of advancing the…
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2010
Two issues of the resistive wall mode (RWM) control code maturity are addressed: the inclusion of advanced mode damping physics beyond the ideal MHD description, and the possibility of taking into account the influence of 3D features of the conducting structures on the mode stability and control. Examples of formulations and computational results a…
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2010
The stability and resonant field response of current driven resistive wall modes are numerically studied for DIII-D [J. L. Luxon, Nucl. Fusion 42 , 614 (2002)] low pressure plasmas. The resonant field response of the feedback-stabilized resistive wall mode is investigated both analytically and numerically, and compared with the response from intrin…
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2009
Self-consistent computations are carried out to study the stability of the resistive wall mode RWM in DIII-D J. L. Luxon, Nucl. Fusion 42 , 614 2002 plasmas with slow plasma rotation, using the hybrid kinetic-magnetohydrodynamic code MARS-K [Y. Q. Liu and et al. , Phys. Plasmas 15 , 112503 (2008)]. Based on kinetic resonances between the mode and t…
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2009
We investigate drift kinetic effects on the resistive wall mode (RWM) stability in ITER plasmas, due to the mode resonance with magnetic precession drifts and/or bounce motion of bulk plasma thermal particles. A toroidal drift kinetic model is self-consistently incorporated into the MHD formulation. Self-consistent simulations using the hybrid kine…
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2008
A self-consistent kinetic model is developed to study the stability of the resistive wall mode in toroidal plasmas. This model is compared with other models based on perturbative approaches. The degree of the kinetic modification to the stability of the mode depends on the plasma configurations. Both stabilizing and destabilizing kinetic effects ar…
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2008
An analytical, large aspect ratio, calculation of the drift-kinetic energy perturbation is carried out for the resistive wall mode, due to the mode resonance with the magnetic precession drifts of trapped thermal ions and electrons. Four asymptotic cases are identified and analyzed in detail. Generally, a partial stabilization of the mode is possib…
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2008
Two approaches for studying the damping of resistive wall modes due to wave particle resonant interactions are discussed. One approach uses the eigenfunction from an ideal MHD code combined with the resonant particle damping calculated from a drift-kinetic Sf - method formulation. This perturbative approach treats the wave-particle interaction prec…
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2006
Active control of the resistive wall mode RWM for DIII-D [Luxon and Davis, Fusion Technol. 8 , 441 (1985)] plasmas is studied using the MARS-F code [Y. Q. Liu, and et al. , Phys. Plasmas 7 , 3681 (2000)]. Control optimization shows that the mode can be stabilized up to the ideal wall beta limit, using the internal control coils I-coils and poloidal…
Showing 1 - 10 of 11 UKAEA Paper Results