ITER Instrumentation and Control System towards Long Pulse Operation

Yonekawa, I.; Fernandez, A. Vergara; Fourneron, Jean-Marc; Journeaux, Jean-Yves; Klotz, W.-D.; Wallander, Anders; Team, Codac

doi:10.1585/pfr.7.2505047

Cited by 3 publications

(1 citation statement)

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“…The long usability required for analysis tools poses special requirements on the software chosen and the maintenance capabilities necessary to adapt to changing environments. Open-source software together with off-the-shelf computer hardware is thought of being perfectly suited for these demands 17 . This in particular applies to all non-standardized components like, e.g., the implementation of complex, tailored, and evolving numerical algorithms for equilibrium reconstruction.…”

Section: Introductionmentioning

confidence: 99%

GPEC: A Real-Time–Capable Tokamak Equilibrium Code

Rampp

Preuss

Fischer

2016

Fusion Science and Technology

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A new parallel equilibrium reconstruction code for tokamak plasmas is presented. GPEC allows to compute equilibrium flux distributions sufficiently accurate to derive parameters for plasma control within 1 ms of runtime which enables real-time applications at the ASDEX Upgrade experiment (AUG) and other machines with a control cycle of at least this size. The underlying algorithms are based on the wellestablished offline-analysis code CLISTE, following the classical concept of iteratively solving the Grad-Shafranov equation and feeding in diagnostic signals from the experiment. The new code adopts a hybrid parallelization scheme for computing the equilibrium flux distribution and extends the fast, shared-memory-parallel Poisson solver which we have described previously by a distributed computation of the individual Poisson problems corresponding to different basis functions. The code is based entirely on open-source software components and runs on standard server hardware and software environments. The real-time capability of GPEC is demonstrated by performing an offline-computation of a sequence of 1000 flux distributions which are taken from one second of operation of a typical AUG discharge and deriving the relevant control parameters with a time resolution of a millisecond. On current server hardware the new code allows employing a grid size of 32 × 64 zones for the spatial discretization and up to 15 basis functions. It takes into account about 90 diagnostic signals while using up to 4 equilibrium iterations and computing more than 20 plasma-control parameters, including the computationally expensive safety-factor q on at least 4 different levels of the normalized flux.

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Section: Introductionmentioning

confidence: 99%