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Joaquim Loizu Cisquella

Cette personne a quitté l’EPFL

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Publications associées (64)

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Simulation of plasma turbulence in scrape-off layer conditions: the GBS code, simulation results and code validation

Ambrogio Fasoli, Ivo Furno, Sébastien Jolliet, Joaquim Loizu Cisquella, Paolo Ricci, Christian Gabriel Theiler, Annamaria Mosetto, Federico David Halpern

Based on the drift-reduced Braginskii equations, the Global Braginskii Solver, GBS, is able to model the scrape-off layer (SOL) plasma turbulence in terms of the interplay between the plasma outflow from the tokamak core, the turbulent transport, and the l ...

Iop Publishing Ltd2012

X-point potential well formation in diverted tokamaks with unfavorable magnetic field direction

Basil Duval, Holger Reimerdes, Marco Wischmeier, Joaquim Loizu Cisquella, Mirko Wensing

Fluid simulations of the boundary of fusion plasmas predict the formation of an electric potential well in the vicinity of the X-point in detached divertor conditions with Bt in the unfavorable direction for H-mode access. This potential well arises when t ...

IOP Publishing Ltd2020

Nature of ideal MHD instabilities as described by multi-region relaxed MHD

Joaquim Loizu Cisquella, Antoine Baillod

In this work, the stepped pressure equilibrium code (SPEC) (Hudson et al 2012 Phys. Plasmas 19 112502), which computes the equilibria of the multi-region relaxed magnetohydrodynamic energy principle (MRxMHD), has been upgraded to determine the MRxMHD stabi ...

2022

Structure of pressure-gradient-driven current singularity in ideal magnetohydrodynamic equilibrium

Joaquim Loizu Cisquella

Singular currents typically appear on rational surfaces in non-axisymmetric ideal magnetohydrodynamic (MHD) equilibria with a continuum of nested flux surfaces and a continuous rotational transition. These currents have two components: a surface current (D ...

2023

On the relationship between the multi-region relaxed variational principle and resistive inner-layer theory

Joaquim Loizu Cisquella

We show that the variational energy principle of the multi-region relaxed magnetohydrodynamic (MRxMHD) model can be used to predict finite-pressure linear tearing instabilities. In this model, the plasma volume is sliced into sub-volumes separated by 'idea ...

2023

A comparison between a refined two-point model for the limited tokamak SOL and self-consistent plasma turbulence simulations

Joaquim Loizu Cisquella, Paolo Ricci, Christoph Wersal

A refined two-point model is derived from the drift-reduced Braginskii equations for the limited tokamak scrape-off layer (SOL) by balancing the parallel and perpendicular transport of plasma and heat and taking into account the plasma–neutral interaction. ...

Institute of Physics2017

Pre-sheath density drop induced by ion-neutral friction along plasma blobs and implications for blob velocities

Ambrogio Fasoli, Ivo Furno, Joaquim Loizu Cisquella, Christian Gabriel Theiler

The pre-sheath density drop along the magnetic field in field-aligned, radially propagating plasma blobs is investigated in the TORPEX toroidal experiment [Fasoli et al., Plasma Phys. Controlled Fusion 52, 124020 (2010)]. Using Langmuir probes precisely al ...

Amer Inst Physics2014

Convective cells and blob control in a simple magnetized plasma

Ambrogio Fasoli, Ivo Furno, Joaquim Loizu Cisquella, Christian Gabriel Theiler

Blob control by creating convective cells using biased electrodes is demonstrated in simple magnetized toroidal plasmas. A two-dimensional array of electrodes is installed on a metal limiter to obtain different biasing schemes. Detailed two-dimensional mea ...

American Physical Society2012

Overview of the first Wendelstein 7-X long pulse campaign with fully water-cooled plasma facing components

Joaquim Loizu Cisquella, Mike Machielsen

After a long device enhancement phase, scientific operation resumed in 2022. The main new device components are the water cooling of all plasma facing components and the new water-cooled high heat flux divertor units. Water cooling allowed for the first lo ...

IOP Publishing Ltd2024

Efficient single-stage optimization of islands in finite-β stellarator equilibria

Joaquim Loizu Cisquella, Erol Balkovic, Christopher Berg Smiet

We present single-stage optimization of islands in finite- β stellarator equilibria. Stellarator optimization is traditionally performed as a two-stage process; in the first stage, an optimal equilibrium is calculated that balances a set of competing const ...

American Institute of Physics (AIP)2025

Theory of the scrape-off layer width in inner-wall limited tokamak plasmas

Sébastien Jolliet, Joaquim Loizu Cisquella, Paolo Ricci, Annamaria Mosetto, Federico David Halpern

We develop a predictive theory applicable to the scrape-off layer (SOL) of inner-wall limited plasmas. Using the non-linear flattening of the pressure profile as a saturation mechanism for resistive ballooning modes, we are able to demonstrate and quantify ...

International Atomic Energy Agency2014

Constructing nested coordinates inside strongly shaped toroids using an action principle

Joaquim Loizu Cisquella, Brenno Jason Sanzio Peter De Lucca, Zeno Tecchiolli

A new approach for constructing polar-like boundary-conforming coordinates inside a toroid with strongly shaped cross-sections is presented. A coordinate mapping is obtained through a variational approach, which involves identifying extremal points of a pr ...

Cambridge University Press2024

Turnstile flux as a measure for chaotic transport in magnetic confinement fusion devices

Joaquim Loizu Cisquella, Ludovic Rais, Christopher Berg Smiet

We analyze a measure for the degree of chaos in the magnetic fields of magnetic confinement fusion reactors by calculating the lobe fluxes of turnstiles - a method developed for characterizing transport into and out of resonance zones in Hamiltonian dynami ...

2025

Nonlinear saturation of resistive tearing modes in a cylindrical tokamak with and without solving the dynamics

Joaquim Loizu Cisquella

We show that the saturation of resistive tearing modes in a cylindrical tokamak, as well as the corresponding island width, can be directly calculated with a magnetohydrodynamics (MHD) equilibrium code without solving the dynamics and without considering r ...

Cambridge University Press2023

Properties of a new quasi-axisymmetric configuration

Joaquim Loizu Cisquella

A novel, compact, quasi-axisymmetric configuration is presented which exhibits low fast-particle losses and is stable to ideal magnetohydrodynamic (MHD) instabilities. The design has fast-particle loss rates below 8% for flux surfaces within the half-radiu ...

IOP Publishing Ltd2019

Methodology for turbulence code validation: Quantification of simulation-experiment agreement and application to the TORPEX experiment

Ambrogio Fasoli, Ivo Furno, Joaquim Loizu Cisquella, Davoud Iraji, Paolo Ricci, Christian Gabriel Theiler, Kyle Gustafson

A methodology for plasma turbulence code validation is discussed, focusing on quantitative assessment of the agreement between experiments and simulations. The present work extends the analysis carried out in a previous paper [P. Ricci et al., Phys. Plasma ...

American Institute of Physics2011

Experimental confirmation of efficient island divertor operation and successful neoclassical transport optimization in Wendelstein 7-X

Gregory Vogel, Eduardo Sanchez, Frank Rüdiger Wagner, Alberto Bottino, Jonathan Graves, Thomas Binderup Jensen, Emiliano Fable, Joaquim Loizu Cisquella, Attila Bencze, Jieping Zhu, Jonathan Marc Philippe Faustin, Antoine Baillod, Nicola Vianello, Mike Machielsen

We present recent highlights from the most recent operation phases of Wendelstein 7-X, the most advanced stellarator in the world. Stable detachment with good particle exhaust, low impurity content, and energy confinement times exceeding 100 ms, have been ...

IOP Publishing Ltd2022

Numerical study of delta-function current sheets arising from resonant magnetic perturbations

Joaquim Loizu Cisquella

General three-dimensional toroidal ideal magnetohydrodynamic equilibria with a continuum of nested flux surfaces are susceptible to forming singular current sheets when resonant perturbations are applied. The presence of singular current sheets indicates t ...

2022

Theory-based scaling of the SOL width in circular limited tokamak plasmas

Gilles Arnoux, Ivo Furno, Sébastien Jolliet, Jan Horacek, Benoît Labit, Joaquim Loizu Cisquella, Paolo Ricci, Annamaria Mosetto, Federico David Halpern

A theory-based scaling for the characteristic length of a circular, limited tokamak scrape-off layer (SOL) is obtained by considering the balance between parallel losses and non-linearly saturated resistive ballooning mode turbulence driving anomalous perp ...

IOP Publishing Ltd2013

Erratum: “Unified nonlinear theory of spontaneous and forced helical resonant MHD states” [Phys. Plasmas 24, 040701 (2017)]

Joaquim Loizu Cisquella

2022