Turbulence in magnetized plasmas

The research line on plasma turbulence has been developed in the course of many years, starting from the previous activity on the use of Langmuir probes and magnetic sensors for the study of the edge plasma region properties.

The most recent results concern the identification within the turbulence measured in the outer region of the RFX-mod experiment of a specific type of coherent structures, named drift-Alfvén vortices. They appear as current filaments parallel to the local magnetic field, with an associated density perturbation and electrostatic potential well, and an Alfvénic vortex-like motion taking place in the plane perpendicular to the magnetic field, due to the ExB drift of the fluid. The same kind of structures has also been observed in the Earth's magnetosphere, in conditions which are similar in terms of adimensional plasma parameters.

Other important topics treated in the past are the effect of the velocity shear on the turbulence, the phenomenon of intermittency, the demonstration that, contrary to claims of other authors, the Self Organized Criticality (SOC) paradigm is not appropriate to explain turbulent transport in fusion plasmas, the effect on transport phenomena of the coherent structures present in the turbulence.

Essential bibliography

E. Martines, N. Vianello, D. Sundkvist, M. Spolaore, M. Zuin, M. Agostini, V. Antoni, R. Cavazzana, C. Ionita, M. Maraschek, F. Mehlmann, H. W. Müller, V. Naulin, J. J. Rasmussen, V. Rohde, P. Scarin, R. Schrittwieser, G. Serianni, E. Spada, the RFX-mod team and the ASDEX Upgrade team, Current filaments in turbulent magnetized plasmas, Plasma Physics and Controlled Fusion 51, 124053 (2009).

M. Spolaore, N. Vianello, M. Agostini, R. Cavazzana, E. Martines, P. Scarin, G. Serianni, E. Spada, M. Zuin, V. Antoni, Direct measurement of current filament structures in a magnetic-confinement fusion device, Physical Review Letters 102, 165001 (2009). [pdf]

M. Spolaore, V. Antoni, E. Spada, H. Bergsåker, R. Cavazzana, J. R. Drake, E. Martines, G. Regnoli, G. Serianni, N. Vianello, Vortex-induced diffusivity in reversed field pinch plasmas, Physical Review Letters 93, 215003 (2004). [pdf]

V. Antoni, V. Carbone, R. Cavazzana, G. Regnoli, N. Vianello, E. Spada, L. Fattorini, E. Martines, G. Serianni, M. Spolaore, L. Tramontin, P. Veltri, Transport processes in RFP plasmas: inconsistency with the Self Organized Criticality paradigm, Physical Review Letters 87, 045001 (2001). [pdf]

V. Carbone, L. Sorriso-Valvo, E. Martines, V. Antoni, P. Veltri, Intermittency and turbulence in a magnetically confined fusion plasma, Physical Review E 62, R49 (2000).

V. Antoni, R. Cavazzana, D. Desideri, E. Martines, G. Serianni, L. Tramontin, Electrostatic turbulence and transport in the velocity shear layer of a reversed field pinch plasma, Physical Review Letters 80, 4185 (1998). [pdf]