Fabien Widmer

Is Turbulence able to Generate Magnetic Islands in Tokamaks? Gyrokinetic Simulations of Turbulence-Driven Magnetic Islands in Toroidal Geometry

Fabien Widmer, A. Mishchenko, A. Ishizawa, T. Hayward-Schneider et autres

We report a universal mechanism for turbulence-driven magnetic islands in fusion plasmas. Using gyrokinetic simulations of a linearly stable tearing mode in a large-aspect-ratio toroidal geometry under collisionless conditions, we demonstrate that micro-instabilities generate an $\boldsymbol{E}\times\boldsymbol{B}$ flow that drives magnetic field line …

Turbulence drive and causal generation of vorticity in edge fusion plasmas

G. Dif‐Pradalier, Y. Sarazin, Ph. Ghendrih, Fabien Widmer et autres

The edge of fusion plasmas is particularly important to model as this is where the plasma self-organizes to higher-energy states. From a turbulence point of view, it is a difficult region to model, often marginally stable, possibly deviating from a quasilinear approximation …

fr, de, sg (code pays fourni par la source)

Linear and nonlinear dynamics of self-consistent collisionless tearing modes in toroidal gyrokinetic simulations

Fabien Widmer, E. Poli, A. Mishchenko, A. Ishizawa et autres

We investigate tearing modes (TM) driven by current density gradient in collisionless tokamak plasmas by using the electromagnetic gyrokinetic simulation code ORB5. We elucidate the TM width by simulations for flat profiles, as the absence of background diamagnetic flows implies a small …

jp, de (code pays fourni par la source)

Global linear and nonlinear gyrokinetic simulations of tearing modes

T. Jitsuk, A. Di Siena, M. J. Pueschel, Paul W. Terry et autres

Abstract To better understand multi-scale interactions between global tearing modes and microturbulence in the Madison Symmetric Torus (MST) reversed-field pinch (RFP), the global gyrokinetic code Gene is modified to describe global tearing mode instability via a shifted Maxwellian (SM) distribution consistent with …

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Global Linear and Nonlinear Gyrokinetic Simulations of Tearing Modes

T. Jitsuk, A. Di Siena, M. J. Pueschel, Paul W. Terry et autres

To better understand the interaction of global tearing modes and microturbulence in the Madison Symmetric Torus (MST) reversed-field pinch (RFP), the global gyrokinetic code \textsc{Gene} is modified to describe global tearing mode instability via a shifted Maxwellian distribution consistent with experimental equilibria. …

Numerical tools for burning plasmas

A. Mishchenko, A. Biancalani, Matthias Borchardt, A. Bottino et autres

Abstract The software stack under development within a European coordinated effort on tools for burning plasma modelling is presented. The project is organised as a Task (TSVV Task 10) under the new E-TASC initiative (Litaudonet al2022Plasma Phys. Control. Fusion64034005). This is a …

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The problem of capturing marginality in model reductions of turbulence

C. Gillot, G. Dif‐Pradalier, Y. Sarazin, C. Bourdelle et autres

Abstract Reduced quasilinear and nonlinear (gradient-driven) models with scale separations, commonly used to interpret experiments and to forecast turbulent transport levels in magnetised plasmas, are tested against nonlinear models without scale separations (flux-driven). Two distinct regimes of turbulence—either above threshold or near …

fr, de, nl (code pays fourni par la source)

Author Correction: Transport barrier onset and edge turbulence shortfall in fusion plasmas

G. Dif‐Pradalier, Ph. Ghendrih, Y. Sarazin, E. Caschera et autres

“Their relative magnitudes are estimated through radial (0.95 ≤ r / a ≤ 1.0), poloidal (0 ≤ θ ≤ 2 π ), toroidal (0 ≤ φ ≤ π /5) and temporal (0 ≤ t Ω ci ≤ 50,000) averaging”.

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Transport barrier onset and edge turbulence shortfall in fusion plasmas

G. Dif‐Pradalier, Ph. Ghendrih, Y. Sarazin, E. Caschera et autres

Abstract Magnetic confinement fusion offers the promise of sustainable and safe energy production on Earth. Advanced experimental scenarios exploit the fascinating yet uncommon ability of confined plasmas to bifurcate into states of enhanced performance upon application of additional free energy sources. Self-regulation …

fr, jp, de (code pays fourni par la source)

Gyrokinetic particle-in-cell simulations of electromagnetic turbulence in the presence of fast particles and global modes

A. Mishchenko, A. Bottino, T. Hayward-Schneider, E. Poli et autres

Abstract Global simulations of electromagnetic turbulence in circular-flux-surface tokamak and ASDEX-Upgrade geometry, tearing instabilities and their combination with the electromagnetic turbulence, nonlinear Alfvénic modes in the presence of fast particles and their combination with the electromagnetic turbulence and global electromagnetic turbulence in …

de, fr, ch, jp (code pays fourni par la source)

Overview of the TCV tokamak experimental programme

H. Reimerdes, M. Agostini, Edoardo Alessi, S. Alberti et autres

Abstract The tokamak à configuration variable (TCV) continues to leverage its unique shaping capabilities, flexible heating systems and modern control system to address critical issues in preparation for ITER and a fusion power plant. For the 2019–20 campaign its configurational flexibility has …

ch, us, it, fr, de, nl, cz, gb, be, pl, ua, se, es, si, fi, at (code pays fourni par la source)

Transport in Fusion Plasmas: Is the Tail Wagging the Dog?

G. Dif‐Pradalier, Ph. Ghendrih, Y. Sarazin, E. Caschera et autres

fr, ca (code pays fourni par la source)