Author: Mikhail Dorf
Requested Type: Poster
Submitted: 2017-03-16 11:47:55
Co-authors: M. Dorr, D. Ghosh, J. Hittinger, W. Lee, R. Cohen
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Continuum kinetic modeling of cross-separatrix plasma transport with COGENT*
M. Dorf1, M. Dorr1, D. Ghosh1, J. Hittinger1, W. Lee2, and R. Cohen3
1Lawrence Livermore National Laboratory, Livermore, CA 94550
2UC San Diego, La Jolla, CA 92093
3CompX, Del Mar, CA 92014Retired (LLNL)
The first continuum kinetic calculations are presented for the axisymmetric cross-separatrix transport of plasma at the edge of a tokamak, including 2D self-consistent variations of an the electrostatic potential. The model solves the full-F gyrokinetic equations for ion species coupled to the long-wavelength limit of a vorticity equation for the electric field. Ion-ion Coulomb collisions are described by using the full nonlinear Fokker-Plank operator. The simulations are performed with a finite-volume code COGENT, which employs arbitrary mapped multi-block technology to handle X-point geometry. The paper also presents recent progress towards extending simulation time for collisional divertor plasmas. To that end, the an Implicit-Explicit (IMEX) infrastructure, which enables implicit treatment of selected terms, has been implemented within the COGENT code. As a practical example, the IMEX scheme is applied to the Fokker-Plank operator, demonstrating significant speed-up of COGENT calculations in strongly-collisional regimes. Finally, the status of 5D COGENT and progress toward the a full edge turbulence code is described.
*Work performed for USDOE, at LLNL under contract DE-AC52-07NA27344.