Abstract
Three dimensional magnetic fields in tokamaks can induce forced magnetic reconnection (FMR) and produce magnetic islands on resonant surfaces. Conventional analytic solutions to FMR focus on describing the time asymptotic state given a steady-state field error. The focus of this work is to understand the nonlinear dynamics of mode penetration, an evolution from a high-slip, flow-screened metastable equilibrium into a low-slip, field-penetrated metastable equilibrium. In this work, we extend previous work by incorporating a temporally varying external magnetic field as a simple model for a magnetohydrodynamic (MHD) event that produces resonant magnetic perturbations. Proof-of-principle, extended-MHD, NIMROD computations vary parameterizations of the transient external perturbation to probe the threshold for mode penetration. We test these computational results against analytical theory that captures the temporal evolution properties of the electromagnetic and viscous forces during and after a transient. We find qualitative agreement between computational and analytical results. However, computational tools are necessary to accurately capture the threshold conditions for mode penetration induced by an MHD transient.
| Original language | English |
|---|---|
| Article number | 082507 |
| Journal | Physics of Plasmas |
| Volume | 25 |
| Issue number | 8 |
| DOIs | |
| State | Published - Aug 1 2018 |
| Externally published | Yes |
Funding
This research was supported in part by the U. S. Department of Energy (DOE), Office of Science, Office of Fusion Energy Sciences under Grant Nos. DE-FG02-92ER54139 and DE-FG02-86ER53218. The first author was also supported in part by the U. S. DOE Fusion Energy Sciences Postdoctoral Research Program administered by the Oak Ridge Institute for Science and Education (ORISE) for the DOE. ORISE is managed by Oak Ridge Associated Universities (ORAU) under DOE Contract No. DESC0014664. All opinions expressed in this paper are the authors’ and do not necessarily reflect the policies and views of DOE, ORAU, or ORISE. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. This research was supported in part by the U. S. Department of Energy (DOE), Office of Science, Office of Fusion Energy Sciences under Grant Nos. DE-FG02-92ER54139 and DE-FG02-86ER53218. The first author was also supported in part by the U. S. DOE Fusion Energy Sciences Postdoctoral Research Program administered by the Oak Ridge Institute for Science and Education (ORISE) for the DOE. ORISE is managed by Oak Ridge Associated Universities (ORAU) under DOE Contract No. DE-SC0014664. All opinions expressed in this paper are the authors' and do not necessarily reflect the policies and views of DOE, ORAU, or ORISE. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
| Funders | Funder number |
|---|---|
| DOE Office of Science | |
| U. S. DOE Fusion Energy Sciences | |
| U. S. Department of Energy | |
| U.S. Department of Energy | DE-AC02-05CH11231, DE-SC0014664 |
| Office of Science | |
| Fusion Energy Sciences | |
| Oak Ridge Associated Universities | |
| Oak Ridge Institute for Science and Education |