This work focuses on the real-time implementation of an integrated plasma equilibrium control system for RFX-mod2. The proposed architecture exploits Model Predictive Control (MPC) to address the challenging asymmetric constraints imposed by the one-quadrant power converters supplying the poloidal field coils at RFX-mod2. The effectiveness of the proposed solution is demonstrated through numerical simulations of demanding operating scenarios. A sensitivity study on the MPC parameters is presented, aiming at tailoring the control algorithm to reduce the number of decision variables and constraints, hence simplifying the optimization problem to be solved in real-time. The real-time feasibility is then verified by means of Hardware-in-the-Loop (HIL) simulations performed on the RFX-mod2 control host. Different off-the-shelf solvers have been considered when automatically generating the real-time code starting from the Simulink model. The HIL simulations revealed that the choice of the solver has a much stronger impact on the execution time than the complexity of the optimization problem itself.

Time synchronization is a fundamental requirement for the reliable operation of Control and Data Acquisition Systems (CODASs) in large-scale fusion experiments such as the Divertor Tokamak Test (DTT). Distributed diagnostics, sensors, and control subsystems must share a unified time reference to guarantee deterministic data acquisition and stable plasma control. This paper presents the FPGA-based implementation and evaluation of a synchronization system that combines the IEEE 1588 Precision Time Protocol (PTP) with Pulse Per Second (PPS) generation. The proposed platform is built on Zynq UltraScale+ Kria KR260 System-on-Modules (SOMs) running a customized PetaLinux distribution with LinuxPTP utilities. Hardware timestamping is enabled through the integrated Timestamping Unit (TSU) in the Gigabit Ethernet MAC, while a hardware logic module generates PPS signals from the synchronized PTP clock. Experimental validation demonstrates nanosecond-level synchronization with an RMS timing accuracy of approximately 8.5 ns. A detailed analysis of PPS offset, network path delay, and servo adjustments confirms stability of the timing system. The proposed design offers a low-cost, flexible, fully customizable and controllable solution for distributed diagnostic and control systems in fusion facilities.

A critical requirement for MITICA – a full-scale prototype of the heating Neutral Beam Injectors hosted at the Consorzio RFX Neutral Beam Test Facility for the ITER experiment – is the capability to withstand a continuous voltage of 1MV across the vacuum gaps insulating the beam source from the grounded vessel. To validate such feature, a dedicated voltage-holding test campaign was conducted throughout 2024 and 2025 using a full-scale mock-up of the beam source. The tests also involved an accurate characterization of the associated breakdown events: vacuum dielectric failures which result in rapid potential drops and generate strong current discharges. This contribution will present a relative time reconstruction architecture based on cost-effective, embedded RedPitaya (Zynq-7000 FPGA) devices repurposed as timing hubs. These nodes function as configurable trigger multiplexers while simultaneously recording trigger signals as transients to facilitate the offline reconstruction of event sequences. The method allows self-calibration through measuring the static intrinsic delays of the optical fibers and internal logics, generating delay offsets to synchronize acquired waveforms across a sparse, connected-graph topology of both acquisition devices and hubs themselves.

The ITER Neutral Beam Test Facility (NBTF) serves as a crucial testing ground for the development and validation of neutral beam injection systems essential for ITER's fusion power plant. For this purpose two experimental campaigns in the two prototypes (SPIDER and MITICA) are conducted within the NBTF. Collaborative efforts at the NBTF, involving scientists from different institutions across Europe, India and Japan, emphasize the importance of data sharing and advanced computing infrastructures. Common computing platforms facilitate analysis of scientific data, aiding informed decision-making. Remote collaboration tools play a crucial role in fostering communication among global experts. The involvement of EUROfusion and ITER experts in strict collaboration accelerates ITER's neutral beam heating and diagnostic systems development. Moreover, remote participation, data visualization, and efficient operation tools are essential for enhancing accessibility and collaboration in scientific research. These tools enable researchers to remotely access and control experimental facilities, visualize data in real-time, and collaborate with colleagues worldwide. This paper presents the design and implementation of operation tools based on EPICS and MDSplus, developed using Grafana, Python, and NodeJS, to enhance remote participation, data visualization, plant operation and collaboration in fusion experiments. A key improvement in SPIDER's pulse repetition rate, now reaching 300 s, was achieved through pre-approved pulses and automatic repetition, significantly increasing the average daily pulses. By using ITER CODAC standards and open-source tools like PostgreSQL, Redis, Grafana, MDSplus, and EPICS, we have optimized both operations and remote collaborations, improving security and efficiency in real-time trend visualization, automating experimental setup verification, optimizing experimental time and performance using real-time pulse sequence reconfiguration.

This paper presents the Hardware-in-the-loop (HIL) validation of a vertical stabilization algorithm for tokamak plasmas based on the Extremum Seeking (ES). This validation is performed by exploiting the rapid prototyping capabilities of the integrated software environment for the deployment of real-time systems based on MDSplus and MARTe2. Using a rapid prototyping tool, the code generated by Simulink Coder((R)) is automatically wrapped into a module that is executed by the MARTe2 application running on a Linux host. HIL validation is then performed interfacing the real-time host with a plasma model executed on a SCALEXIO dSpace((R)) target. The proposed setup is used to validate the ES-based plasma vertical stabilization algorithm in real time before the experimentation on the TCV tokamak. In particular, the maximum control delay that can be tolerated is also assessed. Copyright (c) 2025 The Authors. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/)