Research on the Tokamak à Configuration Variable addresses a wide range of key questions relevant to ITER and future fusion power plants. Over the past two years, highly productive experimental campaigns have led to major advances across several areas: the ITER baseline scenario; pedestal properties in low-collisionality, peeling-limited conditions; and the development of high- (Formula presented) (Formula presented), non-inductive regimes. Alternative high-confinement scenarios have likewise received significant attention, with remarkable progress in quasi-continuous exhaust operation, X-point radiator plasmas, and negative triangularity configurations. Substantial achievements were also made in the mitigation or benign termination of runaway electron beams, in elucidating fast-ion loss mechanisms, and in improving exhaust behaviour in both conventional and alternative divertor geometries. These experimental results have been strongly supported by advances in modelling and their direct application to the experiment, ranging from gyrokinetic simulations of core and pedestal turbulence to fluid-based studies of scrape-off layer and divertor physics in diverse geometries. Plasma control has taken on an increasingly important role, with model-based and data-driven approaches now closely intertwined with physics studies. This article provides a overview of these recent activities, together with a brief outlook on forthcoming upgrades and next steps.

The effect of resistive MHD in the pedestal predictions for JET-ILW has been investigated, using the Europed workflow (Saarelma et al 2018 Plasma Phys. Control. Fusion 60 014042) with the resistive MHD stability code CASTOR (Kerner et al 1998 J. Comput. Phys. 142 271–303). The inclusion of resistivity in the MHD stability calculations leads to a destabilisation of the peeling-ballooning modes. The effect of resistivity is shown for different plasma conditions with scans of the following parameters: the electron pedestal top density, the electron separatrix density and the normalised plasma pressure. The effect of resistivity is largely dependent on the input electron density pedestal profile, and less dependent on the normalised plasma pressure. Overall, at high temperatures, the predictions performed with ideal and resistive MHD are comparable. At low temperature, resistive effects are not negligible and the resistive MHD predictions produce a pedestal pressure height and gradient lower than ideal MHD predictions. Europed predictions with resistive MHD are also compared to experimental values from power scans and gas scans in JET-ILW. While at low gas both ideal and resistive predictions are reasonable, at high gas the resistive Europed predictions show a better agreement with the experimental pedestal height than ideal predictions. The improvement in the predictions of pedestal gradient and width using resistive MHD is instead much smaller. Due to the sensitivity of the resistive predictions to the stability threshold, the work shows that quantitative conclusions are very uncertain but, nonetheless, a qualitative improvement in the agreement with experimental results compared to ideal MHD has been observed.

JET, the only tokamak capable of operating with deuterium–tritium (D–T) fuel (since TFTR was shutdown in 1999), has provided essential experimental data to support ITER and DEMO design and operation. Within the EUROfusion Tokamak Exploitation Work Package, JET completed its final campaigns (2022–2023), culminating in the third D–T campaign (DTE3). These experiments addressed key challenges in plasma scenarios, exhaust control, and tritium management under reactor-relevant conditions. Significant progress was achieved in demonstrating ITER-like integrated scenarios with impurity seeding, achieving partial divertor detachment and high confinement (H₉₈(y,2) ≈ 0.85) at 3 MA in D–T plasmas. Advanced exhaust regimes such as quasi-continuous exhaust (QCE) and X-point radiator (XPR) were successfully achieved first in D–D and then extended to D–T operation, confirming their relevance for mixed isotope operation. Operational milestones included a new world record of 69 MJ fusion energy in tritium-rich hybrid plasmas and long-pulse H-mode operation up to 60 s, contributing with unique data to the CICLOP database. Physics studies focused on peelinglimited pedestals in support of ITER and improved understanding of edge stability and impurity screening in metallic environments. Extensive usage of the shattered pellet injector (SPI) on JET provided critical information for the design of the ITER disruption mitigation system (DMS). Real-time control systems for D/T ratio control and plasma exhaust were deployed and demonstrated in D–D and D–T, while energetic particle physics investigations unfolded the role of fast ions in turbulence suppression mechanisms. Comprehensive tritium retention studies using gas balance method, post-mortem analysis, and ITER-relevant laser induced desorption spectroscopy (LIDS) diagnostics provided essential input for tritium accountancy strategies. These results are validating the ITER operational concepts, inform DEMO design, and deliver critical experience in nuclear operation and scenario integration.