Perturbations to SOC models as a mechanism for transport control
- Oak Ridge Institute for Science Education, TN (United States)
- Oak Ridge National Lab., TN (United States)
Recently the concept of Self-Organized Criticality (SOC) was advanced as a paradigm for turbulent transport in magnetically confined plasmas. The type of model has the advantage of predicting general features of the transport dynamics and profiles independent of the local instability driving the fluctuations. Such a model predicts profile resiliency, sub-marginal profiles maintaining active transport, intermittency in flux and transport events which have large correlation lengths while the underlying fluctuations have short correlation lengths. Given that many of these features have been observed in experiments, an investigation is made of the dynamics of a perturbed SOC system as a mechanism for the control of transport. One of the problems faced by magnetic confinement devices is the control of the heat and particle fluxes. If the fluxes are very {open_quotes}bursty{close_quotes} then even if the walls and divertor can safely absorb the average flux the instantaneous flux could damage or destroy these surfaces. Additionally, in enhanced confinement regimes (H-mode, VH-mode, Enhanced Reversed Shear modes and such) the limiting factor is often the buildup of a super-critical gradient which gives rise to a sudden large transport event. Computational experiments with a sandpile model of SOC dynamics suggests that some modification of the transport dynamics may be possible with periodic perturbations of the internal sources.
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 489515
- Report Number(s):
- CONF-960354-; TRN: 97:011662
- Resource Relation:
- Conference: International Sherwood fusion theory conference, Philadelphia, PA (United States), 18-20 Mar 1996; Other Information: PBD: 1996; Related Information: Is Part Of 1996 international Sherwood fusion theory conference; PB: 244 p.
- Country of Publication:
- United States
- Language:
- English
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