SciTech Connect

Title: Chaos in plasma simulation and experiment

Chaos in plasma simulation and experiment We investigate the possibility that chaos and simple determinism are governing the dynamics of reversed field pinch (RFP) plasmas using data from both numerical simulations and experiment. A large repertoire of nonlinear analysis techniques is used to identify low dimensional chaos. These tools include phase portraits and Poincard 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 data 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 other 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.
Authors: ; ;
Publication Date:
OSTI Identifier:OSTI ID: 10189483
Report Number(s):DOE/ER/53198--223
ON: DE94001574; BR: AT051011A/AT0530020; TRN: 93:024127
DOE Contract Number:FG02-85ER53198
Resource Type:Technical Report
Resource Relation:Other Information: PBD: Sep 1993
Research Org:Wisconsin Univ., Madison, WI (United States). Plasma Physics Research
Sponsoring Org:USDOE, Washington, DC (United States)
Country of Publication:United States
Language:English
Subject: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; REVERSE-FIELD PINCH; RANDOMNESS; STATISTICAL MODELS; PLASMA SIMULATION; NONLINEAR PROBLEMS; TRAPPED ELECTRONS; NOISE; LYAPUNOV METHOD 700330; PLASMA KINETICS, TRANSPORT, AND IMPURITIES