How the Propagation of Heat-Flux Modulations Triggers E×B Flow Pattern Formation

Y. Kosuga, P. H. Diamond, and Ö. D. Gürcan
Phys. Rev. Lett. 110, 105002 – Published 6 March 2013

Abstract

We propose a novel mechanism to describe E×B flow pattern formation based upon the dynamics of propagation of heat-flux modulations. The E×B flows of interest are staircases, which are quasiregular patterns of strong, localized shear layers and profile corrugations interspersed between regions of avalanching. An analogy of staircase formation to jam formation in traffic flow is used to develop an extended model of heat avalanche dynamics. The extension includes a flux response time, during which the instantaneous heat flux relaxes to the mean heat flux, determined by symmetry constraints. The response time introduced here is the counterpart of the drivers’ response time in traffic, during which drivers adjust their speed to match the background traffic flow. The finite response time causes the growth of mesoscale temperature perturbations, which evolve to form profile corrugations. The length scale associated with the maximum growth rate scales as Δ2(vthi/λTi)ρiχneoτ, where λTi is a typical heat pulse speed, χneo is the neoclassical thermal diffusivity, and τ is the response time of the heat flux. The connection between the scale length Δ2 and the staircase interstep scale is discussed.

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  • Received 19 November 2012

DOI:https://doi.org/10.1103/PhysRevLett.110.105002

© 2013 American Physical Society

Authors & Affiliations

Y. Kosuga1,2,*, P. H. Diamond1,3, and Ö. D. Gürcan4

  • 1WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-806, Korea
  • 2Institute for Advanced Study and Research Institute for Applied Mechanics, Kyushu University, Fukuoka 816-8580, Japan
  • 3CASS and CMTFO, University of California at San Diego, California 92093, USA
  • 4Laboratoire de Physique des Plasmas, Ecole Polytechnique, Palaiseau 91128, France

  • *kosugayusuke@gmail.com

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Issue

Vol. 110, Iss. 10 — 8 March 2013

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