ITER

For the first time, the full prototype of the ITER Hard X-Ray (HXR) monitor (HXRM) system has been successfully tested in a tokamak environment during the experimental campaign in the ADITYA Upgrade tokamak located at the Institute for Plasma Research. Unlike conventional HXR diagnostic systems operating in the existing tokamaks, the ITER HXRM is uniquely designed for robustness. In the HXRM system, the UV (Ultraviolet) photons from the scintillator are guided by the optical components to the PMT (Photomultiplier Tube). This approach introduces significant optical attenuation that has a direct impact on the characteristics of the PMT signal. As a result, digital pulse processing algorithms and the I&C (Instrumentation and Control) electronics need reconsideration to work correctly. The initial validation of the HXRM system design was carried out in the laboratory at the Department of Microelectronics and Computer Science, Lodz University of Technology, where the full prototype of the ITER HXRM system was established. The laboratory test validated the design considerations and aided the development of the I&C components. However, the functionality of the system has never been tested in the tokamak environment. The HXRM prototype setup was integrated into the ADITYA Upgrade tokamak and operated during plasma discharges. The data obtained from the plasma discharge allowed verification of the I&C electronics and methodology of the signal transmission, as well as validation of the developed PMT signal simulations. Several test configurations have been tested on the ADITYA Upgrade tokamak, and the preliminary results and observations are reported herein.

Abstract This paper reports on the generic prediction capability of full electromagnetic plasma initiation modelling with DYON, which was carried out for the first time in fusion research by the joint modelling of the International Tokamak Physics Activity—Integrating Operation Scenario group. The following devices were included in the experiment database: VEST (spherical torus, copper coils, Stainless steel wall, R / a = 0.3 m/0.2 m, V v = 3.7 m 3 ), MAST-U (spherical torus, copper coils, C wall, R / a = 0.7 m/0.5 m, V v = 55 m 3 ), EAST (conventional tokamak, superconducting coils, metallic wall, R / a = 1.85 m/0.5 m, V v = 38 m 3 ), DIII-D (conventional tokamak, copper coils, C wall, R / a = 1.67 m/0.65 m, V v = 35 m 3 ), and KSTAR (conventional tokamak, superconducting coils, C wall, R / a = 1.8 m/0.5 m, V v = 55 m 3 ). Despite the different hardware features of the devices, the required operating spaces of the loop voltage induction and prefill gas pressure for inductive plasma initiation in each device were successfully reproduced by the predictive simulations with DYON using only the individual hardware design and the control room input data for each discharge. This successful validation across multiple machines demonstrates that the full electromagnetic DYON modelling can capture the essential physics of inductive plasma initiation. The simulation settings commonly employed for all modelling and the modifications necessary to account for the discrepancies between individual devices are reported. Predictions for ITER based on the multi-machine validation indicate that a wide range of prefill gas pressures exists for the Townsend breakdown and the plasma burn-through (0.01–1.5 mPa).

This study introduces a hybrid methodological approach for personalised clinical decision support, integrating SHACL-based deterministic constraints with Bayesian probabilistic models. The primary goal is to validate the model and demonstrate the benefits of combining encoded clinical knowledge with probabilistic uncertainties in managing complex therapeutic scenarios. The framework was applied to recurrent urinary tract infections (UTIs) in postmenopausal patients, a clinical context marked by high frequency, treatment challenges, and potential conflicts among therapeutic guidelines. Realistic simulated case studies were developed, encompassing both simple clinical profiles and complex situations, such as patients with antibiotic resistance. Each profile was modelled in RDF/Turtle, enabling semantic representation of clinical features and therapeutic rules. The system automatically calculates success and failure probabilities for different therapeutic scenarios, dynamically adapting them based on follow-up data. This allows clinicians to assess not only the initial therapy choice (Case study no. 1) but also the potential addition of supplementary interventions during treatment (Case study no. 2). Results highlight that the proposed hybrid SHACL–Bayesian framework enables tightly coupled deterministic–probabilistic reasoning, where SHACL constraints define the admissible clinical decisions and Bayesian inference operates within this validated space. Compared to deterministic or probabilistic approaches, the combined framework more effectively handles uncertainty, guideline conflicts, and temporal updates. The scientific contribution lies in showing that this integration enhances decision support for recurrent UTIs in postmenopausal patients, providing clinically consistent, transparent, and adaptive therapeutic recommendations aligned with the patient’s evolving condition.

The ITER ICRF antenna [1] has been carefully designed to feature electrical fields below tolerable limits (typically, below 2 or 3 kV/mm depending on the location and orientation) when operating at a maximum voltage of 45 kV. In particular, this allows avoiding arcs. However, as for any high-power RF system, arcs can still occur in the ICRF antenna and its power feeding system, during normal operation and especially during the commissioning. Whenever an arc is detected, the RF power shall be immediately tripped (μs timescale) to avoid strong local energy deposition at the location of the arc. Undetected arcs are forbidden. To this aim, several complementary and redundant Arc Detection (AD) systems are foreseen to protect the ITER ICRF antenna. Among these AD systems is the RADAR Arc Detection (or RAAD [2]) which is currently under evaluation for implementation on the ITER ICRF system To provide a first numerical proof of concept of RAAD, full-wave simulations of the ITER ICRF antenna and its power feeding transmission lines have been performed in the radar bandwidth of operation (up to ~ 350 MHz) with the help of CST Studio Suite and ANSYS HFSS commercial codes. In these simulations, the plasma loading has been approximated by a salty water load (with a relative dielectric permittivity εr = 80 and electrical conductivity σ = 1 S/m), while arcs have been modelled with both perfect electric conductor (PEC) cylinders or lumped element shorts. The obtained S-matrices have been then loaded and processed by the RAAD time-domain circuit simulations and signal processing calculations 2. This paper describes the challenges to simulate the full ITER ICRF antenna with arcs, considering different loading conditions, different materials and different solutions for the arc insertion. It also provides a comparison of the scattering parameters with and without arcs.

The ITER ICRF antenna plug [1, 2] can exhibit resonances at specific frequencies, some of them in the relevant range of frequencies for IC heating. These resonances have been identified as eigenmodes of the coaxial cavity, where the array plays the role of inner conductor [3], that can substantially increase the level of electric fields within the cavity as well as the level of RF losses. As no grounding solution is considered, RF probes should be installed to monitor the RF fields in the port plug cavity and additional simulations of a realistic magnetized plasma are required to properly assess the integration (position, orientation) and their effectiveness. Several numerical tools are available and have been extensively used to simulate the ITER ICRF antenna, such as TOPICA [5] or CST Microwave Studio (MWS [6]), but none of these codes allow to combine realistic geometries, realistic magnetized plasma profiles, and lossy materials. In this paper we pursue the effort started in [8] where a method based on a modal analysis in the cavity was introduced to decouple solving the computationally intensive plasma facing front of the launcher from the cavity. The method reproduces the TOPICA electric fields (with gyrotropic plasma effects) obtained in a given vertical reference plane, in a MWS cavity (including lossy materials) using the multimodal scattering matrix of the cavity obtained with MWS. This method is here applied to several realistic ITER plasma profiles. The recently extracted magnetic fields [9] from the TOPICA modeling results, provide an alternate way to compute the excitation spectrum of the cavity and therefore allow to confirm our results. Accurate levels of RF losses can then be obtained from various plasma profiles and excitation of the antenna straps.

The paper presents a description of a wrapper applicable to plasma physics codes for the purpose of unification within a future platform for modeling the behavior of plasma in a tokamak. Various options for creating modules are considered using the example of codes for calculating various stages of a plasma discharge TRANSMAK and SCENPLINT. The method of their interaction is studied, and using the example of calculation of scenarios of the ITER initial plasma, it is demonstrated that developing such a platform improves the process of solving problems related to plasma modeling and plasma experiment owing to the possibility of simplified combinatorics of calculation modules.