Bibliographic Citation
| Document | For copies of Journal Articles, please contact the Publisher or your local public or university library and refer to the information in the Resource Relation field. For copies of other documents, please see the Availability, Publisher, Research Organization, Resource Relation and/or Author (affiliation information) fields and/or Document Availability. |
|---|---|
| DOI | 10.1063/1.870868 |
| Title | Relaxation oscillations induced by amplitude-dependent frequency in dissipative trapped electron mode turbulence |
| Creator/Author | Terry, P.W. ; Ware, A.S. ; Newman, D.E. (Department of Physics, University of Wisconsin---Madison, Madison, Wisconsin 53706 (United States)) |
| Publication Date | 1994 Dec 01 |
| OSTI Identifier | OSTI ID: 7093400 |
| DOE Contract Number | FG02-89ER53291 |
| Other Number(s) | Journal ID: ISSN 1070-664X; CODEN: PHPAEN |
| Resource Type | Journal Article |
| Resource Relation | Journal Name: Physics of Plasmas; (United States); Journal Volume: 1:12 |
| Subject | 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; TOKAMAK DEVICES; TRAPPED ELECTRONS; TURBULENCE; ELECTRON DENSITY; FREQUENCY DEPENDENCE; INSTABILITY GROWTH RATES; OSCILLATIONS; RELAXATION; CLOSED PLASMA DEVICES; ELECTRONS; ELEMENTARY PARTICLES; FERMIONS; LEPTONS; THERMONUCLEAR DEVICES |
| Description/Abstract | A nonlinear frequency shift in dissipative trapped electron mode turbulence is shown to give rise to a relaxation oscillation in the saturated power density spectrum. A simple non-Markovian closure for the coupled evolution of ion momentum and electron density response is developed to describe the oscillations. From solutions of a nonlinear oscillator model based on the closure, it is found that the oscillation is driven by the growth rate, as modified by the amplitude-dependent frequency shift, with inertia provided by the memory of the growth rate of prior amplitudes. This memory arises from time-history integrals common to statistical closures. The memory associated with a finite time of energy transfer between coupled spectrum components does not sustain the oscillation in the simple model. Solutions of the model agree qualitatively with the time-dependent numerical solutions of the original dissipative trapped electron model, yielding oscillations with the proper phase relationship between the fluctuation energy and the frequency shift, the proper evolution of the wave number spectrum shape and particle flux, and a realistic period. |
| Country of Publication | United States |
| Language | English |
| Format | Medium: X; Size: Pages: 3974-3985 |
| System Entry Date | 2008 Sep 11 |
Top | |
Last Updated: 11/19/2009