Publications by Gergely Papp | EPFL Graph Search

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

Full conversion from ohmic to runaway electron driven current via massive gas injection in the TCV tokamak

Olivier Sauter, Basil Duval, Stefano Coda, Patrick Blanchard, Benoît Labit, Joan Decker, Umar Sheikh, Cristian Galperti, Gergely Papp

Full conversion from ohmic to runaway electron (RE) driven current was observed in the tokamak a configuration variable (TCV) following massive injection of neon through a disruption mitigation valve into a low-density limited circular plasma. Following a ...

IOP Publishing Ltd2022

Physics of runaway electrons with shattered pellet injection at JET

Cristian Sommariva, Javier García Hernández, Gergely Papp

Runaway electrons (REs) created during tokamak disruptions pose a threat to the reliable operation of future larger machines. Experiments using shattered pellet injection (SPI) have been carried out at the JET tokamak to investigate ways to prevent their g ...

2022

Tomographic reconstruction of the runaway distribution function in TCV using multispectral synchrotron images

Basil Duval, Joan Decker, Umar Sheikh, Artur Perek, Gergely Papp

Synchrotron radiation observed in a quiescent Tokamak a Configuration Variable (TCV) runaway discharge is studied using filtered camera images targeting three distinct wavelength intervals. Through the tomographic simultaneous algebraic reconstruction tech ...

IOP Publishing Ltd2021

Disruption mitigation efficiency and scaling with thermal energy fraction on ASDEX Upgrade

Basil Duval, Umar Sheikh, Gergely Papp

Disruption mitigation remains a critical and unresolved issue for ITER. Measurement uncertainties preventing quantification of a system's efficacy remains a significant hurdle in producing and validating a viable disruption mitigation system. This study ad ...

IOP Publishing Ltd2020

Runaway electron synchrotron radiation in a vertically translated plasma

Basil Duval, Joan Decker, Umar Sheikh, Artur Perek, Gergely Papp

Synchrotron radiation observed from runaway electrons (REs) in tokamaks depends upon the position and size of the RE beam, the RE energy and pitch distributions, as well as the location of the observer. We show experimental synchrotron images of a vertical ...

IOP Publishing Ltd2020

Overview of physics studies on ASDEX Upgrade

Olivier Sauter, Basil Duval, Stefano Coda, Timothy Goodman, Benoît Labit, Federico Alberto Alfredo Felici, Alessandro Pau, Cristian Sommariva, Laurie Porte, Antoine Pierre Emmanuel Alexis Merle

The ASDEX Upgrade (AUG) programme, jointly run with the EUROfusion MST1 task force, continues to significantly enhance the physics base of ITER and DEMO. Here, the full tungsten wall is a key asset for extrapolating to future devices. The high overall heat ...

IOP Publishing Ltd2019

Deep neural networks for plasma tomography with applications to JET and COMPASS

Olivier Sauter, Ambrogio Fasoli, Yiming Li, Basil Duval, Jonathan Graves, Duccio Testa, Patrick Blanchard, Henri Weisen, Federico Nespoli, Alessandro Pau

Convolutional neural networks (CNNs) have found applications in many image processing tasks, such as feature extraction, image classification, and object recognition. It has also been shown that the inverse of CNNs, so-called deconvolutional neural network ...

2019

Runaway electron beam stability and decay in COMPASS

Karin Söderström, Joan Decker, Gergely Papp

This paper presents two scenarios used for generation of a runaway electron (RE) beam in the COMPASS tokamak with a focus on the decay phase and control of the beam. The first scenario consists of massive gas injection of argon into the current ramp-up pha ...

IOP Publishing Ltd2019

Role of fast ion pressure in the isotope effect in JET L-mode plasmas

Olivier Sauter, Ambrogio Fasoli, Yiming Li, Basil Duval, Jonathan Graves, Duccio Testa, Patrick Blanchard, Henri Weisen, Federico Nespoli, Alessandro Pau

This paper presents results of JET ITER-like wall L-mode experiments in hydrogen and deuterium (D) plasmas, dedicated to the study of the isotope dependence of ion heat transport by determination of the ion critical gradient and stiffness by varying the io ...

IOP Publishing Ltd2019