Publications by Bernhard Sieglin

Benign termination of runaway electron beams on ASDEX Upgrade and TCV

Basil Duval, Stefano Coda, Joan Decker, Umar Sheikh, Luke Simons, Claudia Colandrea, Jean Arthur Cazabonne, Bernhard Sieglin, Gergely Papp

This paper discusses the development of a benign termination scenario for runaway electron (RE) beams on ASDEX Upgrade and TCV. A systematic study revealed that a low electron density (n e) companion plasma was required to achieve a large MHD instability, ...

Iop Publishing Ltd2024

Scenario optimization for the tokamak ramp-down phase in RAPTOR: A. Analysis and model validation on ASDEX Upgrade

Olivier Sauter, Federico Alberto Alfredo Felici, Simon Van Mulders, Cassandre Ekta Contré, Anna Teplukhina, Bernhard Sieglin

We discuss how the combination of experimental observations and rapid modeling has enabled to improve understanding of the tokamak ramp-down phase in ASDEX Upgrade. A series of dedicated experiments has been performed, to disentangle the effect of individu ...

Iop Publishing Ltd2024

Disruption avoidance and investigation of the H-Mode density limit in ASDEX Upgrade

Alessandro Pau, Federico Alberto Alfredo Felici, Bernhard Sieglin

In recent years a strong effort has been made to investigate disruption avoidance schemes in order to aid the development of integrated operational scenarios for ITER. Within the EUROfusion programme the disruptive H-mode density limit (HDL) has been studi ...

Iop Publishing Ltd2024

Error field detection and correction studies towards ITER operation

Olivier Sauter, Bernhard Sieglin, Leonardo Pigatto

In magnetic fusion devices, error field (EF) sources, spurious magnetic field perturbations, need to be identified and corrected for safe and stable (disruption-free) tokamak operation. Within Work Package Tokamak Exploitation RT04, a series of studies hav ...

IOP Publishing Ltd2024

Dynamic pulse scheduling in ASDEX Upgrade: Disruption avoidance and investigation of the H-Mode density limit

Federico Alberto Alfredo Felici, Alessandro Pau, Bernhard Sieglin

Operation of a tokamak device requires the coordinated operation of a multitude of systems. The sequence of operations during a discharge is both too complex and fast for human interaction. A common way of operation is a predefined sequence of operations w ...

2023

The X-Point radiating regime at ASDEX Upgrade and TCV

Holger Reimerdes, Christian Gabriel Theiler, Marco Wischmeier, Umar Sheikh, Artur Perek, Bernhard Sieglin

Future fusion reactors require a safe, steady-state divertor operation. With deep divertor detachment, which is typically induced by impurity seeding, the radiation concentrates in a small region at the X-point or on closed flux surfaces above the X-point. ...

Elsevier2023

Real-time implementation of the high-fidelity NBI code RABBIT into the discharge control system of ASDEX Upgrade

Federico Alberto Alfredo Felici, Bernhard Sieglin

For the first time, a real-time capable NBI code, which has a comparable fidelity to the much more computationally expensive Monte Carlo codes such as NUBEAM, has been coupled to the discharge control system of a tokamak. This implementation has been done ...

IOP Publishing Ltd2023

Developments on actuator management, plasma state reconstruction, and control on ASDEX Upgrade

Olivier Sauter, Federico Alberto Alfredo Felici, Mengdi Kong, Simon Van Mulders, Bernhard Sieglin

In present day tokamaks, the role of the control research is to support the physics experiments and to prepare technologies for future devices such as ITER and DEMO. This paper presents the developments done under the MST1 program collaboration on ASDEX Up ...

2021

Integrated Real-Time Supervisory Management for Off-Normal-Event Handling and Feedback Control of Tokamak Plasmas

Olivier Sauter, Alessandro Pau, Federico Alberto Alfredo Felici, Cristian Galperti, Anna Ngoc Minh Trang Vu, Bernhard Sieglin

For long-pulse tokamaks, one of the main challenges in the control strategy is to simultaneously reach multiple control objectives and to robustly handle in real-time (RT) unexpected events [off-normal-events (ONEs)] with a limited set of actuators. We hav ...

2021

X-point radiation, its control and an ELM suppressed radiating regime at the ASDEX Upgrade tokamak

Marco Wischmeier, Bernhard Sieglin

Future fusion reactors require a safe, steady state divertor operation. The required detached operation is, in tokamaks with metal walls, usually achieved by seeding of impurities, such as nitrogen. With strong seeding levels, the dominant radiation is emi ...

IOP Publishing Ltd2021