Coherent structures and anomalous transport in reversed field pinch plasmas

• The results leading to the identification of coherent structures emerging from the background turbulence in the edge region of the reversed field pinch experiments EXTRAP-T2R and RFX are reviewed. These structures have traits of vortices in velocity field and blobs in density, and the reconstruction of their spatial structure and of their time evolution is discussed focusing on the analysis tools applied. The role of these structures in the particle anomalous transport is addressed, showing that their collisions can contribute up to 50% the total particle losses. This process is shown to be responsible for bursts in particle flux and it is found to set a characteristic collision time, which is in agreement with the statistical properties of laminar times for particle flux bursts.

Ämnesord

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

Nyckelord

velocity shear-layer

electrostatic turbulence

edge turbulence

magnetized plasma

reynolds stress

diii-d

tokamak

intermittency

fluctuations

confinement

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