N. Zhang Y. Q. Liu P. Piovesan V. Igochine D. L. Yu S. Wang G. Q. Dong G. Z. Hao G. L. Xia W. J. Chen L. Liu J. Q. Li X. Bai
Resistive plasma response to the n = 1 (n is the toroidal mode number) RMP field is systematically investigated for a high-beta hybrid discharge on ASDEX Upgrade. Both linear and quasi-linear response are modelled using the MARS-F and MARS-Q codes, respectively. Linear response computations show a large internal kink response when the plasma centra…
Preprint PublishedY. Liu S.A. Sabbagh I.T. Chapman S. Gerasimov Y. Gribov T.C. Hender V. Igochine M. Maraschek G. Matsunag M. Okabayashi E.J. Strait
The high-frequency noise measured by magnetic sensors, at levels above the typical frequency of resistive wall modes, is analyzed across a range of present tokamak devices including DIII-D, JET, MAST, ASDEX Upgrade, JT-60U, and NSTX. A high-pass filter enables identification of the noise component with Gaussian-like statistics that shares certain c…
Preprint PurchaseI.T. Chapman V. Igochine M. Maraschek P.J. Mccarthy G. Tardini The Asdex Upgrade Ecrh Group The Asdex Upgrade Team
Sawtooth control using steerable electron cyclotron current drive (ECCD) has been demonstrated in ASDEX Upgrade plasmas with a significant population of energetic ions in the plasma core and long uncontrolled sawtooth periods. The sawtooth period is found to be minimised when the ECCD resonance is swept to just inside the q = 1 surface. By utilisin…
PublishedIT Chapman JP Graves O Sauter C Zucca O Asunta RJ Buttery S Coda T Goodman V Igochine T Johnson M Jucker RJ La Haye M Lennholm JET-EFDA Contributors
13MW of electron cyclotron current drive (ECCD) power deposited inside the q = 1 surface is likely to reduce the sawtooth period in ITER baseline scenario below the level empirically predicted to trigger neo-classical tearing modes (NTMs). However, since the ECCD control scheme is solely predicated upon changing the local magnetic shear, it is prud…
PublishedV. Igochine I. T. Chapman V. Bobkov S. Günter M. Maraschek D. Moseev G. Pereversev M. Reich J. Stober Asdex Upgrade Team
It is often observed that large sawteeth trigger the neoclassical tearing mode (NTM) well below the usual threshold for this instability. At the same time, fast particles in the plasma core stabilize sawteeth and provide these large crashes. The paper presents results of first experiments in ASDEX Upgrade for destabilization of fast particle stabil…
PublishedI. T. Chapman M. F. De Bock S. D. Pinches M. R. Turnyanskiy Mast Team V. G. Igochine M. Maraschek G. Tardini Asdex Upgrade Team
Sawtooth behavior has been investigated in plasmas heated with off-axis neutral beam injection in ASDEX Upgrade [A. Herrmann and O. Gruber, Fusion Sci. Technol. 44 , 569 (2003)] and the Mega-Ampere Spherical Tokamak MAST [A. Sykes and et al. , Nucl. Fusion 41 , 1423 (2001)]. Provided that the fast ions are well confined, the sawtooth period is foun…
Published