Operation of the Electron Cyclotron system in the ITER new baseline

¹ ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul-lez-Durance, France
² Max-Planck-Institut für Plasmaphysik, Garching, Germany
³ Istituto per la Scienza e Tecnologia dei Plasmi, CNR, 20125 Milano, Italy

^* Corresponding author: mireille.schneider@iter.org

Published online: 7 January 2026

Abstract

The ITER Research Plan (IRP) has undergone significant modifications based on the change of First Wall (FW) material from beryllium (Be) to tungsten (W). Such a change, together with the constraint of achieving Q=10 for 300s with a neutron fluence of ~1% of the total ITER lifetime fluence, calls for a modification of the heating mix, now dominated by Electron Cyclotron Heating (ECH), to ensure robust plasma operation and provide the most flexible operational space, w.r.t. to Ion Cyclotron Heating (ICH) and Neutral Beam Injection (NBI). This contribution gives first a brief overview of the revised heating mix in the new ITER baseline, with a description of the planned new configuration of the EC system, i.e. the set of Upper and Equatorial launchers needed to inject up to 60-67 MW to ITER plasmas. Delivery of this increased power requires the installation of a second equatorial launcher for the DT phase. The various contexts for which the EC system will be applied cover plasma initiation, wall conditioning, heating, current drive, W and MHD control, to achieve high-performance plasmas and ensure the completion of ITER milestones for the various phases of the IRP. The operational strategy for each phase will be described, in terms of optimal choice of launchers, applied power and polarization, taking into account the plasma evolution during a discharge. The operational conditions are adjusted to achieve the best plasma performance while ensuring that stray radiation does not damage in-vessel components.