A nonlinear dynamic model of relaxation oscillations in tokamaks
| Autor: | A. Thyagaraja, F. A. Haas, D. J. Harvey |
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| Rok vydání: | 1999 |
| Předmět: | |
| Zdroj: | Physics of Plasmas. 6:2380-2392 |
| ISSN: | 1089-7674 1070-664X |
| Popis: | Tokamaks exhibit several types of relaxation oscillations such as sawteeth, fishbones and Edge Localized Modes (ELMs) under appropriate conditions. Several authors have introduced model nonlinear dynamic systems with a small number of degrees of freedom which can illustrate the generic characteristics of such oscillations. In these models, one focuses on physically “relevant” degrees of freedom, without attempting to simulate all the myriad details of the fundamentally nonlinear tokamak phenomena. Such degrees of freedom often involve the plasma macroscopic quantities such as pressure or density and also some measure of the plasma turbulence, which is thought to control transport. In addition, “coherent” modes may be involved in the dynamics of relaxation, as well as radial electric fields, sheared flows, etc. In the present work, an extension of an earlier sawtooth model (which involved only two degrees of freedom) due to the authors is presented. The dynamical consequences of a pressure-driven “coherent... |
| Databáze: | OpenAIRE |
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