Magnetic and electrostatic structures measured in the edge region of the RFX-mod experiment

Coherent structures emerging from turbulence background have been detected in the edge region of the RFX-mod Reversed Field Pinch fusion device by using a new and original probe system measuring simultaneously and on the same location magnetic and electrostatic fluctuations. In agreement with theory it has been experimentally found that pressure structures detected in the cross-field plane, often referred in literature as ‘blobs’, correspond to E × B vorticity structures and are associated to current density filaments, oriented along the main magnetic field. The results are compared with those provided by the measured relationship between magnetic fluctuations and coherent structures on HeI emission observed by the Gas Puffing Imaging system, confirming the presence of such structures also at high current regimes.