Experimental investigation of magnetised plasma turbulence is actively pursued in fusion aimed as well as in basic plasma physics toroidal devices. The experimental study of the turbulence in low beta, low temperature magnetised plasmas has demonstrated the presence of spatially localized density fluctuation structures propagating in the background plasma. Such structures are usually associated to a local modification of the electric field. Their formation and evolution are actively investigated. In particular such structures contributes to the anomalous transport and constitutes an efficient mechanism for the ejection of particles and energy from a plasma column towards the edge region, across the magnetic field lines. This topic is a major issue affecting basic plasma physics understanding yet. It is also relevant in connection with the physics of the edge region of fusion aimed devices. Experiments reported here have been performed in the Thorello device, operating at the University of Milano-Bicocca. Here a low temperature, high density steady plasma column can be produced and mantained in a hydrogen low pressure discharge. The plasma column shows a rather high level of fluctuations which have been studied by means of multiple pin electrostatic probes: fairly long time series of fluctuating plasma parameters have been obtained and correlated. Here electron temperature fluctuations have been measured by means of a double probe. A conditional sampling analysis was then performed in order to detect and study the spatiotemporal evolution of structures in a 2D section of the device in the turbulent state. Here we report results obtained by the selection of events connected with enhanced temperature fluctuations at the edge of the plasma column. The detected structures are compared with those observed in connection with density and potential fluctuations confirming the role of such structures in the energy as well as particle flux.
Barni, R., Riccardi, C., Fredriksen, A. (2011). Structure dynamics associated with temperature fluctuations in the magnetised plasma of the Thorello device. In Proceedings of the 38th EPS Conference on Plasma Physics (pp.632-635).
Structure dynamics associated with temperature fluctuations in the magnetised plasma of the Thorello device
BARNI, RUGGERO;RICCARDI, CLAUDIA;
2011
Abstract
Experimental investigation of magnetised plasma turbulence is actively pursued in fusion aimed as well as in basic plasma physics toroidal devices. The experimental study of the turbulence in low beta, low temperature magnetised plasmas has demonstrated the presence of spatially localized density fluctuation structures propagating in the background plasma. Such structures are usually associated to a local modification of the electric field. Their formation and evolution are actively investigated. In particular such structures contributes to the anomalous transport and constitutes an efficient mechanism for the ejection of particles and energy from a plasma column towards the edge region, across the magnetic field lines. This topic is a major issue affecting basic plasma physics understanding yet. It is also relevant in connection with the physics of the edge region of fusion aimed devices. Experiments reported here have been performed in the Thorello device, operating at the University of Milano-Bicocca. Here a low temperature, high density steady plasma column can be produced and mantained in a hydrogen low pressure discharge. The plasma column shows a rather high level of fluctuations which have been studied by means of multiple pin electrostatic probes: fairly long time series of fluctuating plasma parameters have been obtained and correlated. Here electron temperature fluctuations have been measured by means of a double probe. A conditional sampling analysis was then performed in order to detect and study the spatiotemporal evolution of structures in a 2D section of the device in the turbulent state. Here we report results obtained by the selection of events connected with enhanced temperature fluctuations at the edge of the plasma column. The detected structures are compared with those observed in connection with density and potential fluctuations confirming the role of such structures in the energy as well as particle flux.
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