The rotation of a cylindrical plasma column in a magnetic field has been studied in the linear section of the new plasma device Mistral. Under suitable conditions we observe a transition to a turbulent regime characterized by strong, bursty fluctuations at the edge of the column. The detection and the study of the spatio-temporal evolution of structures in the turbulent regime have been performed by means of a new enhanced conditional sampling technique. We have collected evidence of the development of a bent tail emanating from the plasma column. The charged particles inside the structure move along a spiral trajectory resulting in a net radial convection of the plasma to the walls. We show experimentally that a poloidal electric field is present inside the structures leading to the observed outwards radial E x B drift, in agreement with the expectations of recent and past theoretical works.
Barni, R., Riccardi, C., Pierre, T., Leclert, G., Escarguel, A., Guyomarc'H, D., et al. (2005). Formation of spiral structures and radial convection in the edge region of a magnetized rotating plasma. NEW JOURNAL OF PHYSICS, 7, 225.1-225.17 [10.1088/1367-2630/7/1/225].
Formation of spiral structures and radial convection in the edge region of a magnetized rotating plasma
BARNI, RUGGERO;RICCARDI, CLAUDIA;
2005
Abstract
The rotation of a cylindrical plasma column in a magnetic field has been studied in the linear section of the new plasma device Mistral. Under suitable conditions we observe a transition to a turbulent regime characterized by strong, bursty fluctuations at the edge of the column. The detection and the study of the spatio-temporal evolution of structures in the turbulent regime have been performed by means of a new enhanced conditional sampling technique. We have collected evidence of the development of a bent tail emanating from the plasma column. The charged particles inside the structure move along a spiral trajectory resulting in a net radial convection of the plasma to the walls. We show experimentally that a poloidal electric field is present inside the structures leading to the observed outwards radial E x B drift, in agreement with the expectations of recent and past theoretical works.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.