research

mistralThe linear plasma device Mistral, operating at the CNRS research unit in Marseille (France), is a modern plasma source, aimed to study the turbulent regime and the anomalous transport in magnetized plasmas, a major unsolved problem affecting both our basic plasma physics understanding and the performances of fusion aimed devices. The device produces a rotating magnetized plasma column with a sharp boundary, a configuration displaying interesting analogies with the edge region of Tokamaks.

Research performed in collaboration with PLASMAPROMETEO has been focused on the experimental study of coherent structures and on advanced statistical analysis of the turbulent state of the device.
Conditional sampling measurements show the development of spiral structures, triggered by a plasma profile deformation giving rise to the instauration of a density burst. The burst elongates into a tail extending outwards and bending into a spiral due to the lower angular velocity in the edge region. The tail grows up until it reaches the walls and then vanishes with a lifetime of 200 ms. The burst structure contributes to the turbulent transport since the plasma inside has radial convection outwards by the electric field associated to the structure [1]. This can be grasped also in the movie of the spatio-temporal evolution of the plasma column.

 

 

 

 

Advanced statistical tools have been employed in the analysis of intermittent time series displayed by the plasma parameters in the turbulent steady state. Characterization of different turbulent regimes has been performed and the relation with the non-diffusive transport mechanisms has been understood [2].

» Further information is available in papers published in scientific and popular reviews:

[1] “Radial convection of plasma structures in a turbulent rotating magnetized plasma column”,
Th.Pierre, A.Escarguel, D.Guyomarc’h, R.Barni and C.Riccardi,
Physics Review Letters  92, 065004.1-4 (2004).

[2] “Statistical analysis of correlations and intermittency of a turbulent rotating column in a magnetoplasma device”,
S. Magni, H. E. Roman, R. Barni,C. Riccardi, Th. Pierre, D. Guyomarc’h and P. Devynck,
Physical Review E 72, 026403.1-7 (2005).

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