Z. Yan G.R. Mckee R.J. Groebner P.B. Snyder T.H. Osborne M.N. Beurskens K.H. Burrell
Detailed 2D measurements of long-wavelength density fluctuations in the pedestal region with beam emission spectroscopy during the period between edge localized modes (ELMs) indicate two distinct bands of fluctuations propagating in opposite poloidal directions in the plasma frame: one lower frequency band (50–150 kHz) advects in the ion-diamagne…
PublishedR. Scannell M. Beurskens P.G. Carolan A. Kirk M. Walsh T. O’Gorman T.H. Osborne
Deconvolution of Thomson scattering (TS) profiles is required when the gradient length of the electron temperature ( T e ) or density ( n e ) are comparable to the instrument function length ( R ). The most correct method for deconvolution to obtain underlying T e and n e profiles is by consideration of scattered signals. However, deconvolution at …
PublishedP. Mantica C. Angioni C. Challis G. Colyer L. Frassinetti N. Hawkes T. Johnson M. Tsalas P. C. Devries J. Weiland B. Baiocchi M. N. A. Beurskens A. C. A. Figueiredo C. Giroud J. Hobirk E. Joffrin E. Lerche V. Naulin A. G. Peeters A. Sal
New transport experiments on JET indicate that ion stiffness mitigation in the core of a rotating plasma, as described by Mantica et al. [ Phys. Rev. Lett. 102, 175002 (2009) ] results from the combined effect of high rotational shear and low magnetic shear. The observations have important implications for the understanding of improved ion core con…
PublishedR. Scannell M. Beurskens M. Kempenaars G. Naylor M. Walsh T. O’Gorman R. Pasqualotto
Absolute calibration of LIDAR Thomson scattering systems on large fusion devices may be achieved using rotational Raman scattering. The choice of calibrating gas molecule presents different options and design trade-offs and is likely to be strongly dependent on the laser wavelength selected. Raman scattering of hydrogenic molecules produces a very …
PublishedS. González J. Vega A. Murari A. Pereira M. Beurskens JET-EFDA Contributors
Massive amounts of data generated by fusion machines (such as JET) require developing automatic methods for data analysis. Edge-localized modes (ELMs) are instabilities occurring in the edge of H-mode plasmas. The aim of this work is to develop an automatic off-line method for identifying and locating ELMs. This method uses Universal Multi-Event Lo…
PublishedG P Maddison A E Hubbard J W Hughes J A Snipes B Labombard I M Nunes M N A Beurskens S K Erents M A H Kempenaars B Alper S D Pinches M Valovic R Pasqualotto A Alfier E Giovannozzi JET EFDA Contributors
Experiments on the Alcator C-Mod and JET tokamaks with identical values of nondimensional variables at the pedestal top are expected to have the same local plasma transport for a ratio > 4 in absolute size and thus can help to clarify other effects in pedestal formation. At the high and low fields (7.9 T, 1.4 T respectively) involved, natural-densi…
PublishedY. Liang H. R. Koslowski P. R. Thomas E. Nardon B. Alper P. Andrew Y. Andrew G. Arnoux Y. Baranov M. Bécoulet M. Beurskens T. Biewer M. Bigi K. Crombe E. De La Luna P. De Vries W. Fundamenski S. Gerasimov C. Giroud M. P. Gryaznevich N.
Type-I edge-localized modes (ELMs) have been mitigated at the JET tokamak using a static external n 1 perturbation field generated by four error field correction coils located far from the plasma. During the application of the n 1 field the ELM frequency increased by a factor of 4 and the amplitude of the D signal decreased. The energy loss per ELM…
PublishedM. J. Walsh M. Beurskens P. G. Carolan M. Gilbert M. Loughlin Et Al
The maximum temperature expected in ITER is in the region of 40 keV and the minimum average density of approximately 310 19 m -3 is also expected. The proven capability, convenience, and port occupancy of the LIDAR Thomson scattering approach, demonstrated on JET, makes it an excellent candidate for ITER. Nonetheless, there are formidable design ch…
Published