Design of a High Resolution Probe Head for Electromagnetic Turbulence Investigations in W7-X

An insertable probe head called high resolution probe (HRP) has been developed at Consorzio reversed field experiment in the framework of the EUROfusion S1 work program and in collaboration with IPP Greifswald, to study the electrostatic and electromagnetic features of turbulence in the edge region of Wendelstein 7-X using the multipurpose manipulator. This paper reports the design development of the HRP diagnostic head, from the choice of the sensors to the engineering design. The assumptions and evaluations supporting the main design choices, together with the R&D tests carried out to check the most critical parts, are described in detail.