From a physics discharge program to device control—Linking the scientific and technical world at Wendelstein 7-X

Abstract

Wendelstein 7-X is designed to be a steady state experiment. One discharge may last up to 30 min and will be divided into many segments (elementary experimental program parts). Physics programs need to be pre-planned and technical parameters need to be adjusted in the long run. The technical parameters are a complete set of parameters for all participating components, which describe their behavior within a segment. To enable the diagnosticians to focus on physical experiment parameters only, an abstraction layer above the technical parameters has been developed, the so-called high level parameters. The high level parameters specify a subset of the technical parameters on a physics level and are therefore used to hide technical details. During ordinary program planning, the diagnosticians only see and work with these physics parameters. Having finished editing, the high level parameters will be mapped by a user-defined transformation function onto technical parameters. For all technical parameters which are not defined by the high level parameters, the default values will be taken from one particular predefined pattern. Hence a complete segment is defined by a set of high level parameters including a pattern. In comparison to shot-based and other existing experiments, this is an entirely new, scientifically oriented approach to plan experiments. The motivation and concept of the high level parameters will be discussed. The successful implementation of this concept at the W7-X CoDaC prototype – the small stellarator experiment WEGA – will be presented.