Abstract Details
Abstracts
Author: Qingjiang Pan
Requested Type: Pre-Selected Invited
Submitted: 2017-03-17 11:57:14
Co-authors: Frank Jenko, Daniel Told
Contact Info:
UCLA
PAB 4-341
Los Angeles, CA 90095
USA
Abstract Text:
Edge plasmas present a few challenges for gyrokinetic simulations that are absent in tokamak cores. Among them are large fluctuation amplitudes and plasma-wall interactions in the open field line region. To explore the possibility of applying existing core-turbulence codes to edge plasmas, a 1D+1V code is derived from the widely used code GENE. The code employs a delta-f splitting technique and is able to simulate open systems with large electrostatic fluctuations. With inclusion and proper discretization of the parallel nonlinear term, it becomes equivalent to a full-f code and the delta-f splitting causes no fundamental difficulty in handling large fluctuations. The loss of particles to the wall is accounted for by using a logical sheath boundary, which is implemented in the context of a finite-volume method. The code is benchmarked for the well-established parallel transport problem in the scrape-off layer during edge-localized modes. The parallel heat flux deposited onto the divertor target is compared with previous simulation results and shows good agreement.
To continue the effort of applying GENE to edge plasmas, we are extending the 3D+2V x-global version of GENE to simulate the electrostatic turbulence in the Large Plasma Device (LAPD) at UCLA. Similar to the turbulence in the scrape-off layer, LAPD turbulence features strong collisions, parallel streaming, cross-field turbulent transport, and particle loss at the parallel boundary. As in the 1D+1V work, the major efforts are being devoted to testing numerical schemes for the parallel nonlinear term and implementing an open floating sheath boundary. In addition, a full-f Lenard-Bernstein collision operator is implemented.
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