D. C. McDonald et al, Status of the ITPA paper “Recent progress of the ITPA global H-mode

confinement and pedestal databases”, Kyoto, 18-20th Apr 2005

1/5

Status of the ITPA paper “Recent progress of the ITPA global H-mode confinement and pedestal

databases”

Aim of paper:

• To provide a single reference for users who wish to use DB3v13 or the scalings derived from it– Review data added since DB2

– Review subsets and fitting methods used in recent years

– Summarise available scalings and give recommended ones

• Key issues concerning the whole ITPA group– Completion of tokamak descriptions

– Reaching a consensus on approved scalings for one and two term models

D C McDonald, J G Cordey, K Thomsen, O Kardaun,....

D. C. McDonald et al, Status of the ITPA paper “Recent progress of the ITPA global H-mode

confinement and pedestal databases”, Kyoto, 18-20th Apr 2005

2/5

Section 3: DB3v13 datasets

• 4 main datasets and weightings

• Extended standard set ( IAE2004S = 1 )

• Non-Ohmic D set ( DB3DONLY = 1 )

• ITER-like ( IAE2004S = 1 )

• Pedestal set ( IAE2004S = 1 , with pedestal data )

• Review of errors in the parameters

• Condition of datasets

No real issues

D. C. McDonald et al, Status of the ITPA paper “Recent progress of the ITPA global H-mode

confinement and pedestal databases”, Kyoto, 18-20th Apr 2005

3/5

Section 4: Power law scalings of E

• Ordinary least squares

• Errors in variables

• Principal components

• Pantula method

• PEP model (just reference)

• Dimensionless parameters

• Methods for applying Kadomstev constraints

• More restricted models (g-Bohm, ES)

• Effect of ELM Type

• Do small (Type III) ELMs fit the same scalings?

No real issues

D. C. McDonald et al, Status of the ITPA paper “Recent progress of the ITPA global H-mode

confinement and pedestal databases”, Kyoto, 18-20th Apr 2005

4/5

Section 5: Alternative models for E

• Other variables

• Density peaking, shape, power peaking

• Two term models

• Core and pedestal models

• Interaction models

No real issues

D. C. McDonald et al, Status of the ITPA paper “Recent progress of the ITPA global H-mode

confinement and pedestal databases”, Kyoto, 18-20th Apr 2005

5/5

Section 6: Conclusion

• Recommended scalings

• Summary of scalings, together with a table showing recommended scalings

• Propose we include a set of scalings with a discussion of which to use and in which instance

• IPB98(y,2) (New dataset is still consistent with this using OLS)

• A one term EIV fit (preferred method as error analysis shows OLS is incorrect)

• A two term (although we show, following JGC’s paper, that pedestal data is very poorly conditioned, and so one terms are preferred)

• Discuss a beta independent scaling, as this scaling has been shown on the large ITER-like machines JET and DIII-D. However, cannot recommend as this is not consistent with the whole of DB3.

• Impact on ITER

• POPCON plots and brief description (not a main aim of the paper)

Agree position on scalings