Speaker
Description
GyM is a linear plasma device (LPD) operating at Istituto per la Scienza e Tecnologia dei Plasmi, CNR, Milan, with the aim of studying the plasma-material interaction (PMI) for magnetic confinement nuclear fusion applications [1]. It is part of the portfolio of the EUROfusion facilities and one of the LPDs of the EU Contracting Party involved in the IEA Technology Collaboration Programme on PWI.
This contribution reviews the upgrade of GyM, named “BiGyM”, currently underway as part of the NEFERTARI project funded by NextGenerationEU. The aim of the upgrade is to extend the accessible parameter space from plasma densities of 10$^{16}$–10$^{17}$ m$^{-3}$ and ion fluxes of 10$^{20}$–10$^{21}$ m$^{-2}$s$^{-1}$, suitable for reproducing the ion and charge-exchange neutral fluxes impinging on the main chamber wall of tokamaks, such as ITER, towards 10$^{18}$–10$^{19}$ m$^{-3}$ and 10$^{22}$–10$^{23}$ m$^{-2}$s$^{-1}$, which are more representative of divertor conditions. This will be achieved by installing two helicon plasma sources, each delivering 10 kW of power via 13.56 MHz RF birdcage antennas [2]. In addition, a new sample exposure system has been developed to reproduce the operating conditions of ITER divertor plasma-facing components by heating the samples up to 1500 K and applying a negative bias voltage down to –300 V, thereby enabling precise control over the energy of the incident ions. Finally, GyM’s PMI diagnostic capabilities will also be enhanced through the implementation of a picosecond laser-induced breakdown spectroscopy, ps-LIBS, enabling in situ characterisation of material composition changes and hydrogen isotope retention. With the procurement phase scheduled to conclude by Jan. 2026, BiGyM is expected to achieve first plasma by Apr. 2026, with PMI experiments planned for late 2026.
Acknowledgments
This work has been carried out within the framework of Italian National Recovery and Resilience Plan (NRRP), funded by the European Union - NextGenerationEU (Mission 4, Component 2, Investment 3.1 - Area ESFRI Energy - Call for tender No. 3264 of 28-12-2021 of Italian University and Research Ministry (MUR), Project ID IR0000007, MUR Concession Decree No. 243 del 04/08/2022, CUP B53C22003070006, "NEFERTARI – New Equipment for Fusion Experimental Research and Technological Advancements with Rfx Infrastructure").
References
[1] A. Uccello, et al., Front. Phys. 11, 1108175 (2023)
[2] Ph. Guittienne, et al., Plasma Sources Sci. Technol. 30, 075023 (2021)
