S. Saarelma A. Järvinen M. Beurskens C. Challis L. Frassinetti C. Giroud M. Groth M. Leyland C. Maggi J. Simpson JET Contributors
The H-mode pedestal plays an important role in determining global confinement in tokamaks. In high triangularity H-mode experiments in Joint European Torus with the ITER-like wall (JET-ILW), significantly higher pedestal temperature and global confinement have been achieved with nitrogen seeding. The experimentally observed increase in pedestal hei…
Preprint PublishedP. Bohm M. Aftanas P. Bilkova E. Stefanikova O. Mikulin R. Melich F. Janky J. Havlicek D. Sestak V. Weinzettl J. Stockel M. Hron R. Panek R. Scannell L. Frassinetti A. Fassina G. Naylor M. J. Walsh
The core Thomson scattering diagnostic (TS) on the COMPASS tokamak was put in operation and reported earlier. Implementation of edge TS, with spatial resolution along the laser beam up to~1/100 of the tokamak minor radius, is presented now. The procedure for spatial calibration and alignment of both core and edge systems is described. Several furth…
PublishedS. Saarelma M.N.A. Beurskens D. Dickinson L. Frassinetti M.J.Leyland C.M. Roach EFDA-JET Contributors
The pedestal profile measurements in high triangularity JET plasmas show that with low fuelling the pedestal width decreases during the ELM cycle and with high fuelling it stays constant. In the low fuelling case the pedestal pressure gradient keeps increasing until the ELM crash and in the high fuelling case it initially increases then saturates d…
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…
Published