Publications by Joaquim Loizu Cisquella

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

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 ...

AIP Publishing2022

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

Jieping Zhu, Jonathan Graves, Eduardo Sanchez, Joaquim Loizu Cisquella, Xiaoxue Han, Nicola Vianello, Jonathan Marc Philippe Faustin, Alberto Bottino, Emiliano Fable, Thomas Binderup Jensen, Attila Bencze, Antoine Baillod, Mike Machielsen, Michel Haas, Ajay Kumar, Shuai Liu, Hui Wang, Hartmut Zohm, Konstantinos Avramidis, Frank Rüdiger Wagner, Gregory Vogel, Sheng Xu, Adnan Ali

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

On the non-existence of stepped-pressure equilibria far from symmetry

Joaquim Loizu Cisquella

The Stepped Pressure Equilibrium Code (SPEC) (Hudson et al 2012 Phys. Plasmas 19 112502) has been successful in the construction of equilibria in 3D configurations that contain a mixture of flux surfaces, islands and chaotic magnetic field lines. In this m ...

2021

Parallel convection and E × B drifts in the TCV snowflake divertor and their effects on target heat-fluxes

Basil Duval, Holger Reimerdes, Joaquim Loizu Cisquella, Davide Galassi, Cedric Kar-Wai Tsui, Roberto Maurizio, Mirko Wensing

Parallel convection and E × B drifts act together to redistribute heat between the strike-points mechanisms is enhanced near the secondary X-point and is shown to dominate over heat in the low field side snowflake minus (LFS SF−). The cumulative heat conve ...

2021

First global simulations of plasma turbulence in a stellarator with an island divertor

Paolo Ricci, Joaquim Loizu Cisquella, António João Caeiro Heitor Coelho

We present the results of 3D, flux-driven, global, two-fluid electrostatic turbulence simulations in a 5-field period stellarator with an island divertor. The numerical simulations are carried out with the GBS code, which solves the two-fluid drift-reduced ...

2021

Computation of linear MHD instabilities with Multi-region Relaxed MHD energy principle

Joaquim Loizu Cisquella, Antoine Baillod, Ankit Kumar

Over the last decade, a variational principle based on a generalisation of Taylor's relaxation, referred to as multi-region relaxed magnetohydrodynamics (MRxMHDs) has been developed. The numerical solutions of the MRxMHD equilibria have been constructed us ...

2021

Model for current drive induced crash cycles in W7-X

Joaquim Loizu Cisquella, Ajay Kumar

In the Wendelstein 7-X (W7-X) stellarator, the vacuum rotational transform, ι, has a flat radial profile and does not cross any major rational resonance. Nevertheless, during plasma operation the ι‐profile can be strongly modified by electron cyclotron cur ...

2021

Computation of multi-region, relaxed magnetohydrodynamic equilibria with prescribed toroidal current profile

Jonathan Graves, Joaquim Loizu Cisquella, Antoine Baillod, Ajay Kumar

The stepped-pressure equilibrium code (SPEC) (Hudson et al., Phys. Plasmas, vol. 19, issue 11, 2012, 112502) is extended to allow the computation of multi-region, relaxed magnetohydrodynamics (MRxMHD) equilibria at prescribed toroidal current profile. Toro ...

2021

Experimental verification of X-point potential well formation in unfavorable magnetic field direction

Basil Duval, Holger Reimerdes, Christian Gabriel Theiler, Joaquim Loizu Cisquella, Marco Wischmeier, Cedric Kar-Wai Tsui, Mirko Wensing, Hugo De Oliveira, Sophie Danielle Angelica Gorno, Claudia Colandrea

Recent TCV experiments confirm the predicted formation of an electric potential well, below the magnetic X-point, in configurations with unfavorable

B_t

field direction (ion

\nabla B

drift away from the divertor), that substantially reshapes the typica ...

2020

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

Basil Duval, Holger Reimerdes, Joaquim Loizu Cisquella, Marco Wischmeier, 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 ...

2020

Joaquim Loizu Cisquella

Graph Chatbot

Chat with Graph Search

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

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

On the non-existence of stepped-pressure equilibria far from symmetry

Parallel convection and E × B drifts in the TCV snowflake divertor and their effects on target heat-fluxes

First global simulations of plasma turbulence in a stellarator with an island divertor

Computation of linear MHD instabilities with Multi-region Relaxed MHD energy principle

Model for current drive induced crash cycles in W7-X

Computation of multi-region, relaxed magnetohydrodynamic equilibria with prescribed toroidal current profile

Experimental verification of X-point potential well formation in unfavorable magnetic field direction

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

On the non-existence of stepped-pressure equilibria far from symmetry

Parallel convection and E × B drifts in the TCV snowflake divertor and their effects on target heat-fluxes

First global simulations of plasma turbulence in a stellarator with an island divertor

Computation of linear MHD instabilities with Multi-region Relaxed MHD energy principle

Computation of multi-region, relaxed magnetohydrodynamic equilibria with prescribed toroidal current profile

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

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

Experimental verification of X-point potential well formation in unfavorable magnetic field direction

Model for current drive induced crash cycles in W7-X

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