RFX-mod2 and the NEFERTARI project: A distributed research network for the study of magnetically confined plasmas for fusion

This paper describes the status of the implementation of the upgrades for the RFX-mod2 device, the second major modification of the Reversed Field eXperiment (RFX). The machine’s core update consists of a thin copper stabilizing shell placed inside the vacuum vessel to ensure long-term stability of resistive wall modes (RWM) and enable regimes with fast-rotating tearing modes. A comprehensive modernization of the facility’s technological plants and diagnostics is being carried out within the NEFERTARI project (New Equipment For the Experimental Research and Technological Advancement for the RFX Infrastructure). Funded by the Italian National Recovery and Resilience Plan (NRRP) under Next Generation EU, NEFERTARI aims to strengthen the RFX infrastructure and its network of partners. Significant plant upgrades include: the refurbishment of the main vacuum system and the development of a new glow discharge cleaning (GDC) system based on eight fixed electrodes for more uniform wall conditioning; a major overhaul of the control and data acquisition system, now featuring a high-resolution multichannel acquisition system with over 1500 channels that eliminates the need for analogue integrators; the enhancement edge plasma characterization and of core diagnostics, such as the high-repetition-rate (up to 3 kHz) Thomson Scattering system and the expanded soft x-ray (SXR) tomography; the upgrade of the existing and installation of new reflectometric system; the restoration of the Diagnostic Neutral Beam Injector (DNBI) for spatially resolved ion temperature measurements. Furthermore, the paper highlights the contributions of the Italian laboratory network, including the BiGyM infrastructure for testing innovative plasma-facing components; the ROMAN remote handling facility for in-vessel maintenance development; dedicated laboratories for the development of neutron detectors and for optical diagnostics for the characterization of surfaces, and for high-voltage electrical insulation testing.