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About

What is GKW?


Physics


GKW (Gyro-kinetic Workshop) is a dedicated software tool for the study of turbulence in a tokamak plasma in the local limit. It includes (but is not limited to)

  • the full toroidal geometry of the tokamak (for a real MHD equilibrium through an interface with the CHEASE code)
  • kinetic electrons and an arbitrary number of ion species
  • electro-magnetic effects; both perturbations in the vector potential parallel as well as perpendicular the background magnetic field. (the perpendicular vector potential perturbations are currently being tested)
  • background ExB shear
  • toroidal plasma rotation effects: both the Coriolis as well as the centrifugal force. (The centrifugal effects are currently being tested)

High Performance Computing


GKW runs on a large number of platforms from a desktop computer to the latest supercomputer. Nonlinear runs require a substantial amount of computing power and a large effort has been put in optimizing the efficiency on high performance platforms.


GKW has been designed to run on the present high end computing facilities, and with pure MPI scales well up to 8192 cores (80% efficiency against 95% efficiency obtained for 1024 cores). Hybrid parallelism including OpenMP has recently been implemented, and when optimised it is expected this will allow the code to efficiently scale 4-8x further for a given problem size.

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For a complete description of the code, please see the following paper:
The nonlinear gyro-kinetic flux tube code GKW,
A.G. Peeters, Y. Camenen, F.J. Casson, W.A. Hornsby, A.P. Snodin, D. Strintzi and G. Szepesi,
Computer Physics Communications, 180, 2650 (2009)