Chaos and simple determinism in reversed field pinch plasmas: Nonlinear analysis of numerical simulation and experimental data
- Univ. of Wisconsin, Madison, WI (United States)
In this dissertation the possibility that chaos and simple determinism are governing the dynamics of reversed field pinch (RFP) plasmas is investigated. To properly assess this possibility, data from both numerical simulations and experiment are analyzed. A large repertoire of nonlinear analysis techniques is used to identify low dimensional chaos in the data. These tools include phase portraits and Poincare sections, correlation dimension, the spectrum of Lyapunov exponents and short term predictability. In addition, nonlinear noise reduction techniques are applied to the experimental data in an attempt to extract any underlying deterministic dynamics. Two model systems are used to simulate the plasma dynamics. These are the DEBS code, which models global RFP dynamics, and the dissipative trapped electron mode (DTEM) model, which models drift wave turbulence. Data from both simulations show strong indications of low dimensional chaos and simple determinism. Experimental date were obtained from the Madison Symmetric Torus RFP and consist of a wide array of both global and local diagnostic signals. None of the signals shows any indication of low dimensional chaos or low simple determinism. Moreover, most of the analysis tools indicate the experimental system is very high dimensional with properties similar to noise. Nonlinear noise reduction is unsuccessful at extracting an underlying deterministic system.
- Research Organization:
- Univ. of Wisconsin, Madison, WI (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FG02-85ER53198
- OSTI ID:
- 10189484
- Report Number(s):
- DOE/ER/53198-224; ON: DE94001575; BR: AT051011A/AT0530020; TRN: 93:025549
- Resource Relation:
- Other Information: TH: Thesis (Ph.D); PBD: Sep 1993
- Country of Publication:
- United States
- Language:
- English
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