Tokamak: JET

  Pulse number: 51976

  Shot description,purpose of the shot: 
     Optimised shear discharge with high performance and strong ITB's

  Contact persons: Robert Budny, Xavier Litaudon, Xavier Garbet

  Institution:  EFDA-JET

  Date of shot: 20001006

  Time of interest = 6.5s (46.5s in JET PPF time) for strong ITB

  Analysis codes: TRANSP and EFIT (for plasma boundary)

  Run number: 51976C49 at PPPL, available on mdsplus

  Date of analysis: 20081104 TRANSP run by Robert Budny (budny@princeton.edu)
  Resubmission with new TRANSP run using TEQ; fixed VROTM

 Assumptions made for analysis:

  Ti and toroidal rotation velocity profiles from CX measurements.
  Te from ece emission, extrapolated near the edge.
  Ne profiles vs. radius from LIDAR measurements.

  Density of 4 impurity species (Be, C,Ne,Fe) used to produce a Zeff profile. 
  1D bulk radiation is used in the analysis.
  Particle confinement time is calculated from source rates.
  q profile from MSE measurements at 3.8 to 4.8s.
  The q-profile is deeply inverted with a current hole. 
  The TRANSP analysis assumed a upper limit of 20 for q in the hole and
  anomalous fast ion diffusion near the hole for the equilibrium solver.

 Additional information:

  Pulse #51976 is one of the best Optimised Shear JET discharges. 
  Plasma breakdown was assisted by LHCD with the power Plh=2.0MW applied 
  from t=1.4sec until t=3.5 sec.

  The plasma current was ramping up throughout the pulse so that it has
  reached Ip=2.5MA at t=7.0 sec at a toroidal magnetic field Bt=3.4T. 
  The main heating power was applied at t=3.57 sec and reached its full
  capacity (17.0MW of NBI and 4MW ICRH) at t=5.4 sec. 
  Plasma energy was rising throughout the main heating phase, reaching
  the level of 11MJ. Confinement time enhancement factor H89 exceeded
  2.3 shortly before deterioration caused by transition to type-I Elmy
  H-mode.  

  The direction of the toroidal field and plasma current were in the
  normal JET direction - clockwise viewed from above.

  The plasma developed an electron ITB early, and several ITB's 
  during the main heating, including a weak one at 5.2s and a strong one 
  at 5.85s which gradually expanded its footpoint reaching r/a > 0.7 
  shortly before a disruption terminated the discharge. 

  All beam related quantities (energy, particle sources, currents etc)
  have been smoothed to suppress Monte-Carlo noise.
  In the file JET_51976_0d.dat data is given at 6.50 secs. 
  In the file JET_51976_2d.dat data NM1 and NM3 are the caclulated
  densities of D and trace T.
  NIMP contains the impurity density, dominated by carbon.

  Values for kappa and delta in the 0d, 1d and 2d files are from the TRANSP
  output derived from the boundary input definition provided by EFIT.
  kappa = (Zmax-Zmin)/(Rmax-Rmin),   delta = (RGEO - min(R(zmin),R(Zmax)))/a
  XPLIM and SEPLIM are given by EFIT.
  as defined in the standard list of variables.  
  
  The TRANSP run gives a simulated W_dia 15% above the measured value
  and a neutron emission rate 25% above the measured value.

 Publications:  
    1) For a general description of 51976 and its ITB's see
       C.D.Challis, et al. "Influence of the q-profile
       shape on plasma performance in JET", PPCF <44> (2002)
    2) For an analysis of transport and microturbulence linear stability see
        R.V.Budny, et al., "Microturbulence and flow shear in high-
	performance JET ITB plasma", PPCF <44> (2002) 1215
    3) For an analysis of transport and microturbulence nonlinear stability see
       R.V.Budny, et al., "Turbulence, heat, and particle fluxes
       in JET and DIII-D ITB plasmas with highly reversed magnetic
       shear", EPS conference, St.Petersburg (2003)