Abstract
Frequency-domain full-wave solutions to the cold-plasma problem have become ubiquitous in the study of radio frequency power in fusion plasmas. However, recent efforts at extreme levels of geometric fidelity have revealed fundamental limits in the problem size that can be solved by typical sparse direct solver based methods. These limits are of particular importance in the 3D study of RF launchers, where the number of degrees of freedom required can exceed 100 million. In such cases, it would be advantageous to solve the system via iterative means, but due to the large null space of the curl-curl operator, the convergence properties of algorithms like GMRES are poor. Here we present a physics-based preconditioner in the form of a WKB solution and demonstrate the iterative solution to the frequency-domain Helmholtz problem in 1D for several cases ranging from satisfying the WKB approximation to strongly violating it.
Original language | English |
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Title of host publication | 23rd Topical Conference on Radiofrequency Power in Plasmas |
Editors | Paul T. Bonoli, Robert I. Pinsker, Xiaojie Wang |
Publisher | American Institute of Physics Inc. |
ISBN (Electronic) | 9780735420137 |
DOIs | |
State | Published - Sep 16 2020 |
Event | 23rd Topical Conference on Radiofrequency Power in Plasmas - Hefei, China Duration: May 14 2019 → May 17 2019 |
Publication series
Name | AIP Conference Proceedings |
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Volume | 2254 |
ISSN (Print) | 0094-243X |
ISSN (Electronic) | 1551-7616 |
Conference
Conference | 23rd Topical Conference on Radiofrequency Power in Plasmas |
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Country/Territory | China |
City | Hefei |
Period | 05/14/19 → 05/17/19 |
Funding
∗This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).