Impact of toroidal and poloidal mode spectra on the control of non-axisymmetric fields in tokamaks
| Autor: | Shaun Haskey, Dmitri Orlov, Alexander Lukin, Stefan Matejcik, Francesco Romanelli, Nikolas Logan, YoungMu Jeon, Jeremy Hanson, Lionello Marrelli, Carlos Paz-Soldan, Yongkyoon In, Bohdan Bieg, Youwen Sun, Vladislav Plyusnin, José Vicente, Alberto Loarte, Huihui WANG, Brian Grierson, Axel Jardin, Rajnikant Makwana, Matthew J Lanctot, Marco Wischmeier, William Tang, Choong-Seock Chang, Manuel Garcia-munoz |
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| Rok vydání: | 2017 |
| Předmět: |
Physics
Toroid Tokamak Toroidal and poloidal DIII-D PLASMA Atmospheric-pressure plasma Magnetic reconnection Plasma MOMENTUM DISSIPATION Condensed Matter Physics 01 natural sciences 010305 fluids & plasmas Computational physics law.invention Magnetic field law Physics::Plasma Physics 0103 physical sciences Harmonic Atomic physics 010306 general physics |
| Zdroj: | Physics of Plasmas Physics of plasmas 24 (2017): 056117-1–056117-12. doi:10.1063/1.4982688 info:cnr-pdr/source/autori:Lanctot, M. J.; Park, J.-K.; Piovesan, P.; Sun, Y.; Buttery, R. J.; Frassinetti, L.; Grierson, B. A.; Hanson, J. M.; Haskey, S. R.; In, Y.; Jeon, Y. M.; La Haye, R. J.; Logan, N. C.; Marrelli, L.; Orlov, D. M.; Paz-Soldan, C.; Wang, H. H.; Strait, E. J./titolo:Impact of toroidal and poloidal mode spectra on the control of non-axisymmetric fields in tokamaks/doi:10.1063%2F1.4982688/rivista:Physics of plasmas/anno:2017/pagina_da:056117-1/pagina_a:056117-12/intervallo_pagine:056117-1–056117-12/volume:24 |
| ISSN: | 1070-664X |
| DOI: | 10.1063/1.4982688 |
| Popis: | In several tokamaks, non-axisymmetric magnetic field studies show that applied magnetic fields with a toroidal harmonic n = 2 can lead to disruptive n = 1 locked modes. In Ohmic plasmas, n = 2 magnetic reconnection thresholds in otherwise stable discharges are readily accessed at edge safety factors q similar to 3, low density, and low rotation. Similar to previous studies with n = 1 fields, the thresholds are correlated with the "overlap" field computed with the IPEC code. The overlap field quantifies the plasma-mediated coupling of the external field to the resonant field. Remarkably, the "critical overlap fields" at which magnetic islands form are similar for applied n = 1 and 2 fields. The critical overlap field increases with plasma density and edge safety factor but is independent of the toroidal field. Poloidal harmonics m> nq dominate the drive for resonant fields while m < nq harmonics have a negligible impact. This contrasts with previous results in H-mode discharges at high plasma pressure in which the toroidal angular momentum is sensitive to low poloidal harmonics. Together, these results highlight unique requirements for n > 1 field control including the need for multiple rows of coils to control selected plasma parameters for specific functions (e.g., rotation control or ELM suppression). |
| Databáze: | OpenAIRE |
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