SciTech Connect

Title: The dynamics of marginality and self-organized criticality as a paradigm for turbulent transport

The dynamics of marginality and self-organized criticality as a paradigm for turbulent transport A general paradigm, based on the concept of self-organized criticality (SOC), for turbulent transport in magnetically confined plasmas has been recently suggested as an explanation for some of the apparent discrepancies between most theoretical models of turbulent transport and experimental observations of the transport in magnetically confined plasmas. This model describes the dynamics of the transport without relying on the underlying local fluctuation mechanisms. Computations based on a cellular automata realization of such a model have found that noise driven SOC systems can maintain average profiles that are linearly stable (submarginal) and yet are able to sustain active transport dynamics. It is also found that the dominant scales in the transport dynamics in the absence of sheared flow are system scales rather than the underlying local fluctuation scales. The addition of sheared flow into the dynamics leads to a large reduction of the system-scale transport events and a commensurate increase in the fluctuation-scale transport events needed to maintain the constant flux. The dynamics of these models and the potential ramifications for transport studies are discussed.
Authors: ; ; ;
Publication Date:
OSTI Identifier:188629
Report Number(s):CONF-951182--4
ON: DE96004930; TRN: 96:006372
DOE Contract Number:AC05-84OR21400
Resource Type:Conference
Data Type:
Resource Relation:Conference: 37. annual meeting of the American Physical Society Division of Plasma Physics, Louisville, KY (United States), 6-10 Nov 1995; Other Information: PBD: [1995]
Research Org:Oak Ridge National Lab., TN (United States)
Sponsoring Org:USDOE, Washington, DC (United States)
Country of Publication:United States
Language:English
Subject: 70 PLASMA PHYSICS AND FUSION; THERMONUCLEAR DEVICES; TURBULENCE; TRANSPORT THEORY; MAGNETIC CONFINEMENT; PLASMA SIMULATION; SHEAR; PLASMA INSTABILITY; BOHM CRITERION