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Magnetic and Electrostatic Turbulence Island Modulation in the W7-X Boundary

Spolaore M.; Killer C.; Agostinetti P.; Cavazzana R.; Ghiraldelli R.; Grenfell G.; Grulke O.; Knieps A.; Lazerson S.A.; Moresco M.; Martines E.; Neubauer O.; Nocolai D.; Satheeswaran G.; Schweer B.; Vianello N.; W7-X Team

Conference: The 24th International Conference on Plasma Surface Interactions in Controlled Fusion Devices - PSI-24, , Jeju, Korea , 25-29 January 2021 Year: 2021
ISTP Authors:
Raffaele Ghiraldelli
Nicola Vianello
Monica Spolaore
Piero Agostinetti

Keywords: , ,
Research Activitie:

The presence of magnetic island in the boundary of fusion devices is expected to strongly affect the local plasma properties, inducing local flow velocity patterns and perturbing the edge profiles as well as the transport properties. In particular the proximity to the island Xpoint or O-point is found to induce both electrostatic and magnetic turbulence modulation, with experimental evidences in different magnetic configurations. The boundary of the W7-X stellarator experiment is characterized by the presence of a poloidal chain of magnetic islands, whose features depend on the magnetic configuration as defined by the rotational transform, ?/2?. These islands intercept the divertor plates and provide a poloidal series of X-points constituting the island divertor, the concept exploited in the W7-X for the particle and energy exhaust. In this contribution the presence and features of turbulent fluctuations in both electrostatic and magnetic quantities, including the parallel current density fluctuations will be investigated in the Scrape-Off-Layer region of W7-X experiment. To this end a specifically designed insertable probe head was constructed within the framework of EUROfusion WP.S1 work package in collaboration between Consorzio RFX, IPP Greifswald and Forschungszentrum Jülich. The probe head, named High Resolution Probe (HRP) [1,2], was conceived to be installed on the mid-plane multi-purpose fast reciprocating manipulator on W7-X and is suitable for the study of electrostatic and magnetic properties of filaments emerging from turbulence background and characterizing the edge region. In particular the magnetic island related turbulence modulation and the filamentary structure population distribution will be analysed by applying advanced statistical tools First measurements were performed during the W7-X experimental campaign OP1.2b, where in particular the probe was exploring different magnetic configurations. The respective features of the electromagnetic turbulence will be compared.

ID 445439
PRODUCT TYPE Conference Abstract
LAST UPDATE 2022-09-21T16:54:21Z