Augsburg 2006 – scientific programme
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P: Plasmaphysik
P 28: Astrophysikalische Plasmen; Dichte Plasmen 1; Schwerionen- und lasererzeugte Plasmen 2; Staubige Plasmen 4; Theorie 1
P 28.26: Poster
Wednesday, March 29, 2006, 17:30–19:00, Flure
Acting on flute modes and drift waves : open-loop synchronization and generation of turbulence — •Frederic Brochard1, Gerard Bonhomme2, and Etienne Gravier2 — 1Max-Planck-Institut für Plasmaphysik, EURATOM Ass., 17491 Greifswald — 2LPMIA, Universite Henri Poincare, Nancy, France
Flute modes and drift wave dynamics are experimentally investigated in a low-β magnetized cylindrical plasma. A spatiotemporal open-loop synchronization method, successfully tested on drift wave turbulence [1], is applied to flute modes [2]. Control is reached using an octupole exciter, which generates an azimuthally rotating electric field of the same order of magnitude as the one due to the fluctuations. Weakly turbulent Kelvin-Helmholtz and Rayleigh-Taylor states are synchronized in a satisfactory way. However, the efficiency of the control is shown to depend on the relative distance to the exciter and to the location of the velocity shear layer. The eight-plates exciter can be used to destabilize regular modes as well. By adding an incommensurate frequency to the drift-mode, the Ruelle-Takens route to turbulence is easily recovered as the amplitude of the exciter is increased.
[1] C. Schröder et al., Phys. Rev. Lett. 86, 5711 (2001)
[2] F. Brochard et al., Phys. Plasmas 12, 062104 (2005).