Global energy confinement H-mode database for ITER

Abstract

The paper describes the content of an H-mode confinement database that has been assembled for the ITER project. Data were collected from six machines of different sizes and shapes: ASDEX, DIII-D, JET, JFT-2M, PBX-M and PDX. A detailed description of the criteria used in the selection of the data and the definition of each of the variables is given. The paper also presents an analysis of the conditions of the database, the scalings (power law and offset linear) of the data with both dimensional and dimensionless variables, and predictions of the expected confinement time for ITER.

ITER L-Mode Confinement Database

“…As can be seen from the values in the table, there are slight modifications to the K , R, and density scaling coefficients, with the largest differences occuring in the R / a and M,jj dependence. The loss of the high aspect ratio PBX-M data in the limiter dataset compromises the ability to determine the aspect ratio dependence, as discussed in the H-mode database work [7]. Interestingly, there is no dependence of effective mass in this limiter-only dataset; this result has been reported by TFTR based on dedicated isotopic mass dependence experiments [33].…”

“…A discussion of this is found in the first ITER H-mode database paper [7]. Table 10 shows the results of the principal component (P.c.)…”

“…As discussed in Section 3 of the article describing the global H-mode database [7], two useful yardsticks for giving insight into the collinearity of what are believed to be the most important parameters in determining the global confinement scaling are the correlation and principal component matrices.…”

“…direction. As discussed in the H-mode database article [7], collinearity problems exist if E R R 2 1; as a rule, ERR 5 0.25 indicates a well conditioned database. To compute ERR, it is assumed that the standard deviations of the measurement errors in R, R/a, I p , BT, Meff, ne, IG, and P L J h are 0.5%, 1%) 1%, 1%, 10%) 5%) 1%, and 15% respectively, and that any correlations among the errors, most notably between E e and P~, t h , are ignored.…”

“…The original H-mode database, ITERHDB.l, [7] contained confinement data assembled from six tokamaks, and an updated version, ITERHDB.2, was released in 1994 [8]. The H-mode database assembly and analysis effort was significantly more detailed and sophisticated than those of the L-mode efforts.…”