A practical protocol to emulate a reactor scenario on present machines, with application to the ASDEX Upgrade tokamak via predictive modeling

In this work, a novel practical strategy to emulate a reactor scenario on present tokamak experiments is presented. A recipe how to scale several relevant parameters from a hypothetical reactor scenario down to present devices is discussed. Equivalence between the energy flux channels is detailed, and the practical actuation scheme is presented. The application of the proposed protocol on the ASDEX Upgrade tokamak is shown foremost using the virtual flight simulator Fenix, with practical experiments planned for future campaigns

The modeling of a tokamak plasma discharge, from first principles to a flight simulator

A newly developed tool to simulate a tokamak full discharge is presented. The tokamak \u27flight simulator\u27 Fenix couples the tokamak control system with a fast and reduced plasma model, which is realistic enough to take into account several of the plasma non-linearities. A distinguishing feature of this modeling tool is that it only requires the pulse schedule (PS) as input to the simulator. The output is a virtual realization of the full discharge, whose time traces can then be used to judge if the PS satisfies control/physics goals or needs to be revised. This tool is envisioned for routine use in the control room before each pulse is performed, but can also be used off-line to correct PS in advance, or to develop and validate reduced models, control schemes for future machines like a commercial reactor, simulating realistic actuators and sensors behavior

Targeting a Versatile Actuator for EU-DEMO: Real Time Monitoring of Pellet Delivery to Facilitate Burn Control

Core particle fueling, an essential task in the European demonstration fusion power plant EU-DEMO, relies on adequate pellet injection. However, pellets are fragile objects, and their delivery efficiency can hardly be assumed to be unity. Exploring kinetic control of the EU-DEMO1 scenario indicates that such missed-out pellets do cause a considerable problem for keeping a burning plasma. Missed-out pellets can cause a severe drop of plasma density that in turn results in a potential drastic loss of burn power. Efforts are under way at the ASDEX Upgrade (AUG) tokamak aiming to provide real-time monitoring of pellet arrival and announcement of missed-out cases to the control systems. To further optimize the controllers, system identification experiments have been performed to identify the dynamic response of the system to the actuator

Real-time model-based plasma state estimation, monitoring and integrated control in TCV, ASDEX-Upgrade and ITER

To maintain a high-performance, long-duration tokamak plasma scenario, it is necessary to maintain desired profiles while respecting operational limits. This requires real-time estimation of the profiles, monitoring of their evolution with respect to predictions and known limits, and their active control to remain within the desired envelope. Model-based techniques are particularly suitable to tackle such problems due to the nonlinear nature of the processes and the tight coupling among the various physical variables. A suite of physics-based, control-oriented models for the core plasma proles in a tokamak is presented, with models formulated in such a way that powerful methods from the systems and control engineering community can be leveraged to design ancient algorithms. We report on new development and applications of these models for real-time reconstruction, monitoring and integrated control of plasma proles on TCV, ASDEX-Upgrade and simulations for ITER

Loss of neuronal network resilience precedes seizures and determines the ictogenic nature of interictal synaptic perturbations

The mechanisms of seizure emergence, and the role of brief interictal epileptiform discharges (IEDs) in seizure generation are two of the most important unresolved issues in modern epilepsy research. Our study shows that the transition to seizure is not a sudden phenomenon,but a slow process characterized by the progressive loss of neuronal network resilience. From a dynamical perspective, the slow transition is governed by the principles of critical slowing, a robust natural phenomenon observable in systems characterized by transitions between dynamical regimes. In epilepsy, this process is modulated by the synchronous synaptic input from IEDs. IEDs are external perturbations that produce phasic changes in the slow transition process and exert opposing effects on the dynamics of a seizure-generating network, causing either anti-seizure or pro-seizure effects. We show that the multifaceted nature of IEDs is defined by the dynamical state of the network at the moment of the discharge occurrence