Darren McDonald, TFS1 meeting, 20th April /20 Proposed JET 2006 confinement experiments D C McDonald Structure of talk: Hybrid studies ELMy H-mode, multi-machine gyro-radius scan ELMy H-mode, collisionality scan

Darren McDonald, TFS1 meeting, 20th April /20 Hybrid confinement scaling D C McDonald, E Joffrin, T Luce, ….

Darren McDonald, TFS1 meeting, 20th April /20 JET studies: plasmas with  N =2-2.7 H98(y,2) increases with Beta Indicates an improved confinement regime, or a problem with scaling at high  N Absolute values of H98≈1-1.2, lower than DIII-D/AUG Difficult to extrapolate to ITER JET experiments Joffrin, IAEA (2004)

Darren McDonald, TFS1 meeting, 20th April /20 JET to perform further Hybrid studies (>10 sessions) in 2006 – Ascertain that mode is comparable with DIII-D/AUG mode – Document mode – including confinement behaviour JET to contribute and 2006 Hybrid data to the global and profile databases With data from other machines this should enable an assessment of the Hybrid confinement scaling – Is it appropriate to take ELMy H-mode scalings? – Can a separate Hybrid scaling be determined Part of the JET programme involves a Beta scan study – BetaN = 1.5 – 3, does confinement follow ELMy H-mode trend? Aims for 2006

5/20 D. C. McDonald et al, S gyroradius scaling, JET, 19th April 2006 CDB-8: Gyro-radius scaling D C McDonald, C Petty, A Staebler, M Greenwald, C Giroud, I Nunes, G Maddison, H Leggate, I Voitsekhovitch, L Laborde

6/20 D. C. McDonald et al, S gyroradius scaling, JET, 19th April – 4 JET experiments Type I and Type III scans I p = MA close to gyro-Bohm Confirmed Gyro- radius scalings at most ITER-like conditions Error bars still large JET shots have 2-3 times ITER rho*, so 0.5 error translates to a 40% error for ITER Type III ELMy H-modes McDonald, IAEA (2004)

7/20 D. C. McDonald et al, S gyroradius scaling, JET, 19th April 2006 DIII-D experiments: local transport DIII-D studies permitted local transport analysis which also found close to gyro- Bohm-like scaling Error bars still large large radial variation systematic errors momentum mismatch Turbulence L-mode studies show gBohm bhvr, but Bohm-like transport Petty, FS&T (2005) 978 McKee, NF (2001) 1235; Hennequin, PPCF (2004) B121

8/20 D. C. McDonald et al, S gyroradius scaling, JET, 19th April 2006 For ELMy H-modes: DIII-D and JET both matched *= * ITER and  =  ITER In this way the extrapolation to ITER was in one parameter  *  1996 experiment with DIII-D © Blur-vision Result independently validated ITER prediction (figure) Individual machine scans were pretty narrow No turbulence, impurity or pedestal studies Aim: to improve these experiments to provide better ITER estimate and scaling for transport and turbulence ITER Physics Basis (OLD ITER)

9/20 D. C. McDonald et al, S gyroradius scaling, JET, 19th April experimental proposal Produce a multi-machine scan in Gyro-radius at matched (shape, q,  N, *) in ITER relevant conditions JET/DIII-D/AUG/C-Mod involved Machine constraints mean we have opted for q 95 =3.85, betaN=1.5 Start with JET/C-Mod match with DIII-D and AUG to add central points after this data is analysed C-Mod has time scheduled for April-May 2006 Plasmas must be well diagnosed for core, edge, fluctuations and impurity transport. Analysis includes: scaling, particle and thermal transport studies

10/20 D. C. McDonald et al, S gyroradius scaling, JET, 19th April 2006 Proposed shape Use JET/AUG/C-Mod shape developed by I Nunes Same as for G Maddison’s experiments Match is clearly good and comparable with previous JET/DIII-D/AUG/C-Mod experiments

11/20 D. C. McDonald et al, S gyroradius scaling, JET, 19th April 2006 Proposed matched parameters Parameter C-Mod (A) C-Mod (B) C-Mod (C) JET (A) JET (B)JET (C) Trans. Freq. (MHz) R (m) a (m) B (T) I (MA) n (1E19 m^-3) P_gB (MW) W (MJ) TAU_gB (s) R/a3.07 kappa1.7 delta0.45 q_ BETA_N1.30 nu*7.2 B*TAU_gB F_GDL rho*

12/20 D. C. McDonald et al, S gyroradius scaling, JET, 19th April 2006 JET shot list 0.77 MA / 0.86 T, q95=3.85 shot. Tune gas and heating (≈2.0MW) to match BetaN = 1.3 and target density 1.53 MA / 1.72 T shot. Tune for same match (≈3.9MW) 2.58 MA / 2.3 T shot. Tune for same match (≈5.9MW) All plasmas must be well diagnosed: core and pedestal, impurity transport, turbulence, bolometry NBI / ICRH heating schemes Scheduled: June 2006 (test shots in May)

Darren McDonald, TFS1 meeting, 9th June /20 Collisionality scan for core and edge transport D C McDonald, Geoff Cordey, Xavier Garbet, Paola Mantica, Carine Giroud, Irina Voitsekhovitch, Huw Leggate, Alberto Loarte

Darren McDonald, TFS1 meeting, 9th June /20 Background: * scans A * scan experiment varies * at fixed (  *, , q, shape, heating...) In practise, it’s a field scan with I  B, n  B 0, T  B 2 Two previous scans on JET B.  E  * , 2 point, limited profile data B.  E  * , * , 4 point, weak data (low I p, n e ) McDonald et al., IAEA (2004)

Darren McDonald, TFS1 meeting, 9th June /20 * dependence a power law? All * scan experiments show a negative B  E - * correlation Power law fits show a variety of exponents General trend for weaker exponent at smaller *  not a simple power law Theoretically: could represent a transition between transport regimes Leggate et al., EPS (2005) p: -Ve exponent of * scaling B  E  * - p

Darren McDonald, TFS1 meeting, 9th June /20 What do transport theorists say? Connor et al., PPCF (1988); Garbet et al., EPS (2004); Model ( B.  E  * p exponent) Dissipative TEM (1, 4/3, 2) Dissipative TIM (1) Collisionless TEM (0) Collisionless ITG Mode (0) Resistive ballooning (edge only) Zonal flows (neoclassically damped) B.  E  * p exponent 1, 4/3, Ve Leading candidate is kinetic drift wave turbulence with zonal flows, neo-classically damping

Darren McDonald, TFS1 meeting, 9th June /20 Particle transport * is a key parameter for particle transport Previous results indicate a *- peaking correlation – This experiment will largely just add to the DB – Improved TS and EFIT data is of interest here – strong n e peaking will complicate analysis of main experiment He, Ni/Mo, Ne/Ar, will be performed simultaneously Weisen et al., EPS (2004)

Darren McDonald, TFS1 meeting, 9th June /20 ELM energy loss Previous experiments show a falling  W ELM /W ped with increasing * Will collect edge data, so can study the * here Should benefit from improved edge data Loarte et al., PPCF 45 (2003) 1549

Darren McDonald, TFS1 meeting, 9th June /20 Aims of experiment Experiment: 3 point * scan, from *  0.1 (collisionless) to * > 1 (collisional) – Good match of (  *, , q, shape, heating...) essential – Collect core and edge kinetic data, MSE, CX, IR camera Analysis – Analyse discharges for energy (TRANSP), bulk particle (TRANSP) and impurity (UTC-SANCO) transport as well as documenting ELM losses. – Test a series of models for energy, bulk particle and impurity transport. Scheduled: Aug 2006

Darren McDonald, TFS1 meeting, 9th June /20 Pulse list (all same shape) 2.5 MA / 2.6 T, P NBI = MW, unfueled: obtain low * (0.1) reference, based on # Short gas scan 1.8 MA / 1.8 T, P NBI = 10 MW : mid * (0.4), tune power to match  N of reference Gas scan to match  * 1.3 MA / 1.3 T, P NBI = 8 MW : high * (1.4), tune power to match  N of reference Gas scan to match  * 3 shots 2 shots 3 shots 2 shots NB: wall loading should help us maintain density