CF Maggi H Weisen L Horvath F Auriemma R Lorenzini E. Delabie D King D Keeling S Menmuir JET Contributors
Dimensionless identity experiments test the invariance of plasma physics to changes in the dimensional plasma parameters, e.g. ne and Te, when the dimensionless parameters are conserved [1] [2]. However, conditions at the plasma boundary, such as influx of neutral particles, may introduce additional physics. An isotope identit…
Preprint PublishedC.D. Challis S. Brezinsek I. Coffey M. Fontana N. Hawkes D. Keeling D. King G. Pucella E. Viezzer JET Contributors
The initial current ramp phase of JET hybrid plasmas is used to optimise the target q-profile for main heating to allow access to high beta and avoid MHD instabilities. Mixed protium-deuterium experiments, carried out at JET since the installation of the beryllium-tungsten wall, have shown that the q-profile evolution during this Ohmic phase varies…
Preprint PublishedM. Maslov J. Citrin P. Jacquet Y. Kazakov D. L. Keeling D. B. King E. Lerche M. Marin J. Ongena D. Van Eester
As part of the preparation for the second JET DT campaign (DTE2), a series of isotope control experiments in H/D mixtures [1] have shown that NBI fuelling species has only a weak effect on the core isotope composition, which remains determined by the edge H/D ratio and therefore by the injected gas.
Preprint PublishedC.D. Challis S. Brezinsek I. Coffey N. Hawkes D. Keeling D. King G. Pucella E. Viezzer JET Contributors
The initial Ohmic current ramp phase of JET hybrid plasmas, including a current ‘overshoot’ before the main heating, is used to optimise the q-profile shape to allow access to high β and avoid MHD instabilities [1]. Such hybrid plasmas have never been operated using tritium (T) or mixed deuterium-tritium (D-T) fuel. However, experiments with i…
Preprint PublishedL. Horvath C.F. Maggi A. Chankin S. Saarelma A.R. Field E. Belonohy A. Boboc G. Corrigan E.G. Delabie J. Flanagan L. Frassinetti C. Giroud D. Harting D. Keeling D. King M. Maslov G.F. Matthews S. Menmuir S.A. Silburn J. Simpson A.C.C Sips H. Weisen K.J. Gibson JET Contributors
The pedestal structure, ELM losses and linear MHD stability are analysed in a series of JET-ILW H and D type I ELMy H-mode plasmas. The pedestal pressure (pPED) is typically higher in D than in H at the same input power, with the difference mainly due to lower density in H than in D. At the same input power, the pedestal electron pres…
Preprint PublishedI. Turner R. McAdams W. Arter A. Ash M. Barnard D. Ciric I. Day D. Keeling D. King C. Lane M. Nicassio T. Robinson A. Shepherd J. Zacks
Increased neutralisation and hence injected neutral beam power can be achieved by increasing the neutraliser target. This has the potential to increase the loading on the ion source backplate due to backstreaming electrons. Measurements of the backplate power loading due to backstreaming electrons are presented for the JET EP2 neutral beam injector…
Preprint PublishedD.B. King C.D. Challis E.G. Delabie D. Keeling G.F. Matthews S. Silburn JET contributors
The dependence of JET neutron deficit and energy balance on neutral beam (PINI) selection has been investigated experimentally. The discrepancy between neutrons predicted and measured during JET pulses has consistently deviated, with the measured neutrons typically being lower than expected by simulation. A number of investigations into this hav…
Preprint PublishedKrassimir Kirov Yu. Baranov I.S. Carvalho C.D. Challis J. Eriksson D. Frigione L. Garzotti J. Graves P. Jacquet D.L. Keeling E. Lerche P.J. Lomas C. Lowry M. Mantsinen F. Rimini and JET Contributors
Fast ion synergistic effects were studied by predictive modelling of JET best performing pulses for various levels of Neutral Beam (NB) and Radio Frequency (RF) power. Calculated DD neutron yields were analysed with the intention of separating the impact of sheer synergistic effects due to changes in fast ion (FI) distribution function (DF) from su…
Preprint PublishedM. Cecconello W. Boeglin D. Keeling S. Conroy I. Klimek R. V. Perez the MAST team
Experimental evidence is presented of a discrepancy between the predicted and measured D-D fusion products rates on MAST. Both the neutron and proton production rates, measured independently with a neutron camera and charged fusion product detector array, are approximately 40 % lower than those predicted by TRANSP/NUBEAM codes. This deficit is scen…
Preprint PublishedM. Maslov D. King E. Viezzer D. Keeling C. Giroud T. Tala A. Salmi M. Marin J. Citrin C. Bourdelle E. Solano JET contributors
Particle transport is of a great importance for understanding physics of tokamak plasmas and planning future experiments on larger machines such as ITER. The subject was intensively studied in the past, particularly in relation to density peaking and presence of anomalous inward particle convection in L- and H-mode. While in the L-mode case presenc…
Preprint Published