Three-dimensional structures in the torsatron TJ-K

N. Mahdizadeh (1) , F. Greiner (1) , T. Happel (1) , M. Ramisch (1) , U. Stroth (2)

1 IEAP - Institut für Experimentelle und Angewandte Physik [Kiel]
2 IPF - Institut für Plasmaforschung [Stuttgart]

The three-dimensional structure of drift wave turbulence is studied in the low temperature plasma of the torsatron TJ-K.Previous 2D investigations of plasma density and floating potential fluctuations in the poloidal plane have shown that drift waves play the dominant role for the formation of coherent structures and radial transport [U. Stroth, Phys. Plasma, 11, 2558(2004)]. The observed structures are quasi-coherent and show a scaling with the drift scale rho_s=c_s/w_ci. The distinguished characteristic of drift waves is the dynamic parallel to the magnetic field, i.e. k_||=/=0. Therefore a detailed understanding requires fully three dimensional investigations. A combination of a 2D-movableprobe and a poloidal 8x8 matrix of electrostatic probes is used to investigate the parallel dynamics in TJ-K. A heuristic model is proposed, which shows that the parallel dynamic in TJ-K is described by the occurrence of large, spatially localized coherent structures with drift wave dynamics.

Mots clés: confined plasma; drift waves; turbulence; langmuir probes; probe arrays

Domaines: Physique des plasmas [physics.plasm-ph]

N. Mahdizadeh, F. Greiner, T. Happel, M. Ramisch, U. Stroth. Three-dimensional structures in the torsatron TJ-K. 2004. ⟨hal-00001818⟩