L. Horvath M. Maslov P.A. Schneider C.F. Maggi L.Frassinetti B. Lomanowski R.B. Morales D. Nina S. Saarelma J. Simpson G. Corrigan D.I. Refy M.Brix T. Pereira M. Vecsei JET Contributors
The relative role of particle transport and edge fuelling in setting the H-mode density pedestal is still a key open question [1]. Although reduced pedestal models have proven successful in predicting the pedestal pressure for a wide range of plasma scenarios [2,3,4], they lack a first principle based, predictive model for the edge density. Predict…
Preprint PublishedD. Brunetti J. P. Graves C. J. Ham S. Saarelma
We propose a resistivity-beta driving mechanism aimed at explaining the appearance of free boundary long wavelength global instabilities in high-beta diverted tokamaks. These perturbations resemble very closely the RWM (resistive wall mode) phenomenon. Performing a proper toroidal analysis, we show that the magnetohydrodynamic stability is worsened…
PreprintP.-Y. Li D. R. Hatch B. Chapman-Oplopoiou S. Saarelma C. M. Roach M. Kotschenreuther S. M. Mahajan the MAST Team
The results of a recent gyrokinetic analysis of turbulent transport driven by the electron temperature gradient (ETG) in the MAST pedestal are presented. During the inter-ELM period, the buildup rate of the electron density gradients is faster than that of the electron temperature gradients, possibly indicating the presence of an active electron th…
PreprintM Maslov E. Lerche F. Auriemma C.D. Challis A. Chomiczewska A. Dal Molin J. Eriksson J. Garcia J. Hobirk I. Ivanova-Staknik Ph. Jacquet A. Kappatou Y. Kazakov D. Keeling D.B. King V. Kiptily K. Kirov D. Kos R. Lorenzini E. De La Luna C.F. Maggi J. Mailloux P. Mantica M. Marin G. Matthews I. Monakhov M. Nocente G Pucella D. Rigamonti F. Rimini S. Saarelma Z. Stancar H. Sun M. Tardocchi D. Van Eester JET contributors
In JET deuterium-tritium (D-T) plasmas, the fusion power is produced through thermonuclear reactions and reactions between thermal ions and fast particles generated by neutral beam injection (NBI) heating or accelerated by electromagnetic wave heating in the ion cyclotron range of frequencies (ICRF). To complement the experiments with 50/50 D/T …
PreprintD. Brunetti J. P. Graves C. J. Ham S. Saarelma
External kink modes, believed to be the drive of the beta-limiting Resistive Wall Mode, are strongly mitigated by the presence of a separatrix. We thus propose a novel mechanism explaining the appearance of long-wavelength global instabilities in free boundary high-beta diverted tokamaks, retrieving the experimental observables within a physical…
PreprintT. Wilson S.J. Freethy M. Henderson A Köhn-Seeman I. Konoplev S. Saarelma D. Speirs R.G.L. Vann the STEP team
The UK’s Spherical Tokamak for Energy Production (STEP) reactor design program is now exclusively investigating concepts using microwave-based heating and current drive (HCD) systems. Electron Bernstein Wave (EBW) HCD is a relatively immature technology compared to Electron Cyclotron (EC) HCD but is of interest due to the promise of high current…
PreprintS. Saarelma J.W. Connor P. Bilkova P. Bohm A.R. Field L. Frassinetti R. Fridstrom A. Kirk JET Contributors*
The neutral ionisation model proposed by R J Groebner et al. (Phys Plasmas 9 2134 (2002)) to determine the plasma density profile in the H-mode pedestal, extended to include charge exchange processes in the pedestal stimulated by the ideas of Mahdavi et al. ((Phys Plasmas 10 3984 (2003)). The model is then teste…
Preprint PublishedD. Brunetti C. J. Ham J. P. Graves E. Lazzaro S. Nowak A. Mariani C. Wahlberg W. A. Cooper E. R. Solano S. Saarelma L. Frassinetti M. Fontana A. Kleiner G. Bustos Ramirez E. Viezzer JET contributors
The analysis of quiescent discharges exhibiting edge harmonic magnetoydrodynamic activity in the JET-Carbon wall machine is presented. It is observed that the quiescent phase with multiple-n harmonic oscillations is sustained until a threshold in pedestal electron density and collisionality is crossed. The macroscopic pedestal parameters associated…
Preprint Published