Anomalous diffusion of plasma particles in electrostatic turbulence and systems of magnetic islands.
Project ID:IAA1043201
Provider:Grant Agency of the Academy of Sciences
Period:Jan 01, 2002 - Dec 31, 2004
Recipient - coordinatorInstitute of Plasma Physics, Czech Academy of Sciences, Prague
Principal Investigator:Ing. Ladislav Krlín, DrSc.
Co-recepient(s) / PI(s):Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, Prague -- Ing. Vojtěch Svoboda
Co-investigators from IPP, , , , , , ,

Aims of the project: It is generally accepted that the low frequency turbulence in tokamaks causes of a diffusion of particles. Recently, we have proposed a new simple model of diffusion, based on ExB diffusion of particles in a spatially periodical stationary potential field. We found two regimes of an anomalous diffusion: random-walk and Lévy-walk type and generatation of a radial electric field. The project supposes to generalize the mentioned approach for the case of potentials with limited spatial and temporal correlations given analytically and experimentally and wishes to show whether the found phenomena will survive in the generalized model. We shall estimate the difference between the usually used drift approximation and the full description, which includes the cyclotron motion. We will also investigate the anomalous diffusion of particles due to their interaction with magnetic islands. The project covers establishing of the analytical backgrounds and numerical codes for the mentioned mechanisms.

Progress/Results: Numerical solution of the dynamics of plasma particles has shown that in a model of a turbulent plasma potential as well as in the potential, experimentally detected is an anomalous diffusion of carbon ions faster than that the diffusion of electrons.

Results:

Pánek R., Krlín L., Taskhakaya D., Kuhn S., Stöckel J., Pavlo P., Tender M., Svoboda V., Petržílka V.: Anomalous diffusion and radial electric field generation due to edge plasma turbulence. Contributions to Plasma Physics 44 [1-3] (2004) 203-204. [ Abstract ]
[International Workshop on Plasma Edge Theory in Fusion Devices/9th./. San Diego, 03.09.2003-05.09.2003]

Krlín L., Pánek R., Petržílka V., Stöckel J., Svoboda V., Kuhn S., Tskhakaya D., Tendler M.: Anomalous impurity diffusion in models of tokamak edge plasma turbulence. Czechoslovak Journal of Physics 54 [suppl.C] (2004) C157-C163. [ Abstract ]
[Symposium on Plasma Physics and Technology/21st./. Praha, 14.06.2004-17.06.2004]

Krlín L., Stöckel J., Svoboda V.: Stochastic (ExB) diffusion of ions in a spatially periodical potential field. Plasma Physics and Controlled Fusion 41 [3] (1999) 339-353.