Topology and transport: Difference between revisions

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The aim of this page is to introduce and report progress on the activities included in the research project ''Influence of global flows and their topology on transport in turbulent plasmas'', funded by the Spanish Ministry of Science and Innovation through the grant ENE2009-07247. The members of the research team are:
The aim of this page is to introduce and report progress on the activities included in the research project ''Influence of global flows and their topology on transport in turbulent plasmas'', funded by the Spanish [http://www.micinn.es Ministry of Science and Innovation] through the grant ENE2009-07247. The members of the research team are:


* Iván Calvo (Principal Investigator), Laboratorio Nacional de Fusión, Asociación EURATOM-CIEMAT, Madrid,
* Iván Calvo (Principal Investigator), [[Laboratorio Nacional de Fusión]], Asociación EURATOM-CIEMAT, Madrid,
* Benjamín Carreras, BACV Solutions Inc., Oak Ridge, Tennessee & University of Alaska,
* Benjamín Carreras, BACV Solutions Inc., Oak Ridge, Tennessee & University of Alaska,
* Irene Llerena, Universidad de Barcelona,
* Irene Llerena, Universidad de Barcelona,
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* Raúl Sánchez, Oak Ridge National Laboratory, Oak Ridge, Tennessee &  Universidad Carlos III, Madrid.
* Raúl Sánchez, Oak Ridge National Laboratory, Oak Ridge, Tennessee &  Universidad Carlos III, Madrid.


The aim of this proposal is to advance in the understanding of turbulent transport in  
The aim of this proposal is to advance the understanding of turbulent transport in  
magnetically confined fusion plasmas by studying the topology and dynamics of global flows. We will  
magnetically confined fusion plasmas and study the impact of the topology and dynamics of global flows on it. We will  
tackle concrete problems in three broad research areas of toroidally confined plasmas:  topology of  
tackle concrete problems in three broad research areas of toroidally confined plasmas:  topology of  
structures in the presence of turbulence (or, in short, "the topology of flows"), non-diffusive transport,  
structures in the presence of turbulence (or, in short, "the topology of flows"), non-diffusive transport,  
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and during the next three years, we plan to study the problem in pressure-gradient-driven turbulence,  
and during the next three years, we plan to study the problem in pressure-gradient-driven turbulence,  
with a possible extension to gyrokinetic models. For this we will make use of Computational  
with a possible extension to gyrokinetic models. For this we will make use of Computational  
Homology. An important tool will be the software developed by the Computational Homology Project
Homology. An important tool will be the software developed by the [http://chomp.rutgers.edu Computational Homology Project (CHomP)] which, in particular, computes some topological invariants  
(CHomP, see http://chomp.rutgers.edu) which, in particular, computes some topological invariants  
(the Betti numbers) of three-dimensional spaces. We will investigate the possibility of developing or  
(the Betti numbers) of three-dimensional spaces. We will investigate the possibility of developing or  
using other tools which allow to improve the numerical resolution of the calculations.  
using other tools which allow to improve the numerical resolution of the calculations.


== Non-diffusive transport ==
== Non-diffusive transport ==
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Recent experimental results in the TJ-II stellarator prove the existence of long-distance correlations
Recent experimental results in the TJ-II stellarator prove the existence of long-distance correlations
in the electrostatic potential around the bifurcation point for the emergence of the plasma edge sheared
in the electrostatic potential around the bifurcation point for the emergence of the plasma edge sheared
flow layer <ref>[http://prl.aps.org/abstract/PRL/v100/i21/e215003 M. A. Pedrosa et al., Phys. Rev. Lett. 100, 215003 (2008)]</ref. In Ref. <ref>[http://www.iop.org/EJ/abstract/-search=68892777.7/0741-3335/51/6/065007 I. Calvo et al., Plasma Phys. Control. Fusion 51 065007 (2009)]</ref> we have formulated a phenomenological model which based on the paradigm of flow shear generation by Reynolds stress and turbulence supression by shear. We suggest that the experimental results might be an indirect evidence of the development of poloidally asymmetric zonal flows.
flow layer <ref>[http://prl.aps.org/abstract/PRL/v100/i21/e215003 M.A. Pedrosa et al., Phys. Rev. Lett. '''100''', 215003 (2008)]</ref>. Trying
 
to understand these results from a theoretical point of view, we have formulated a phenomenological model
<ref>[http://www.iop.org/EJ/abstract/-search=68892777.7/0741-3335/51/6/065007 I. Calvo et al., Plasma Phys. Control. Fusion '''51''', 065007 (2009)]</ref> based on the  
paradigm of flow shear generation by Reynolds stress and turbulence suppression by  
shear. We suggest that the experimental results might be an indirect evidence of the development of poloidally asymmetric zonal flows.


== References ==
== References ==
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<references />