Hannover 2010 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 11: Invited Talks Windisch, Manz, Loffhagen, Hauser

P 11.2: Hauptvortrag

Mittwoch, 10. März 2010, 11:30–12:00, B 305

Structure formation in drift-wave turbulence — •Peter Manz, Mirko Ramisch, and Ulrich Stroth — Institut für Plasmaforschung, Universität Stuttgart

Turbulence is studied for more than 250 years. Although famous scientists as Reynolds, Kolmogorov, Heisenberg or Landau worked on this topic, a general mathematical or physical solution could not be found yet. This is because turbulence corresponds to a highly nonequilibrium state, where dynamical processes on micro and macro-scales are closely coupled.

Many current problems in climate, economy and energy research are directly or indirectly related to turbulence. Also for the major part of particle and energy losses in toroidal fusion plasmas turbulence is responsible. Of special interest is the spontaneous generation of transport barriers triggered by azimuthally symmetric, band like shear flows called zonal flows, which can decorrelate the turbulence and absorb energy from the fluctuations. As in rotating geophysical fluids turbulence in magneticallay confined plasmas is two-dimensional. Energy cascades from small to large scales such as zonal flows or hurricanes. The contribution will give a general overview of the physical mechanisms active in the turbulent cascades. The fundamental processes are investigated using data from the stellarator TJ-K. The physics of turbulence suppression by sheared flows will be explained by a somewhat different mechanism as the generally expected one.