S Mordijck R A Moyer A Kirk P Tamain D Temple G R Mckee E Nardon
Recent experiments show the impact of Resonant Magnetic Perturbations on the density [O Schmitz et al Plasma Phys. Control. Fusion 50 124029 (2008); T E Evans et al Nucl. Fusion 48 024002 (2008); A Kirk et al Nucl. Fusion 50 024002 (2008); Y Liang et al Phys. Rev. Lett. 98 265004 (2007)], leading to a so-called density pump-out. Previous comparison…
PublishedD. Dickinson S. Saarelma R. Scannell A.Kirk C.M.Roach H.R.Wilson
Pedestal profiles that span the ELM cycle have been obtained and used to test the idea that the pedestal pressure gradient in MAST is limited by the onset of Kinetic Ballooning Modes (KBMs). During the inter-ELM period of a regularly type I ELM-ing discharge on MAST, the pressure pedestal height and width increase together while the pressure gradie…
PublishedS. Saarelma O.J. Kwon A. Kirk Mast Team
We study the effects of the X-point configuration on ELM triggering peeling and ballooning modes by using fixed boundary equilibria and modifying the plasma shape to approach the limit of a true X-point. The current driven pure peeling modes are asymptotically stabilised by the X-point while the stabilising effect on ballooning modes depends on the…
PublishedA. Kirk Yueqiang Liu E. Nardon P. Tamain P. Cahyna I. Chapman P. Denner H. Meyer S. Mordijck D. Temple The Mast Team
Experiments have been performed on MAST using internal (n=3) resonant magnetic perturbation coils. The application of the RMPs to L-mode discharges has shown a clear density pump out when the field line pitch angle at the low field side of the plasma is sufficiently well aligned with the applied field. The application of the RMPs before the L-H tra…
PublishedA. Kirk H.W. Muller A. Herrmann M. Kocan V. Rohde P. Tamain The Asdex Upgrade Team
The radial propagation of type-I ELMs in ASDEX Upgrade has been measured using a number of techniques. The most reliable technique uses a filament probe to measure the time difference between two separated probes and yields a mean radial velocity obtained of ~1.5 kms -1 . The radial velocity calculated using a time of flight technique suffers from …
PublishedG. De Temmerman E. Delchambre A. Kirk S. Lisgo P. Tamain
A long wavelength range infrared camera (LWIR) has been installed on MAST to compliment the existing medium wave infrared system. Simultaneous LWIR/MWIR temperature measurements have been made in the lower and upper divertors of MAST. As expected, the LWIR system is less sensitive to disturbances from hot spots on the surface. A thorough correction…
PublishedP Tamain A Kirk E Nardon B Dudson B Hnat The Mast Team
The impact of Resonant Magnetic Perturbations (RMPs) on the edge of MAST L-mode plasmas is studied using a mid-plane reciprocating probe equipped with a Gundestrup probe head. A strong impact on the characteristics of the ion saturation current fluctuations is observed just inside the separatrix, with a broadening of the power spectrum and an asymm…
PublishedYueqiang Liu A. Kirk E. Nardon
The plasma response to resonant magnetic perturbation RMP and nonresonant perturbation fields is computed within a linear, full toroidal, single-fluid resistive magnetohydrodynamic framework. The response of resonant harmonics depends sensitively on the plasma resistivity and on the toroidal rotation. The response of nonresonant harmonics is not se…
PublishedV.Rozhansky E.Kaveeva P. Molchanov I.Veselova S.Voskoboynikov D.Coster A.Kirk S.Lisgo E.Nardon
The impact of resonance magnetic perturbations (RMP) on the structure of the edge transport barrier has been studied. A new model for the density pump-out mechanism during the stochastization of the plasma edge is proposed. The observed phenomena are explained as a result of the impact of the ambipolar electric field, which is modified during RMP, …
Published