Publications related to Magnetic reconnection

Shedding light on the MRI-driven dynamo in a stratified shearing box

We study the magneto-rotational instability (MRI) dynamo in a geometrically thin disc (H/R < 1) using stratified zero net (vertical) flux shearing box simulations. We find that mean fields and electromotive forces (EMFs) oscillate with a primary frequency ...

2024

Gyrokinetic simulations of turbulence in magnetic fusion plasmas using a delta-f PIC scheme with evolving background

Moahan Murugappan

Using the GKEngine code which simulates an electrostatic plasma with adiabatic electron response under a sheared-slab geometry, an attempt at developing a hybrid approach between the delta-f and full-f schemes to describe plasma profiles exhibiting high fl ...

EPFL2024

Global fluid simulation of plasma turbulence in stellarators with the GBS code

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

The implementation of three-dimensional magnetic fields, such as the ones of stellarators, in the GBS code (Ricci et al 2012 Plasma Phys. Control. Fusion54 124047; Giacomin et al 2022 J. Comput. Phys.464 111294) is presented, and simulation results are dis ...

IOP Publishing Ltd2024

Inter-discharge optimization for fast, reliable access to ASDEX Upgrade advanced tokamak scenario

Olivier Sauter, Federico Alberto Alfredo Felici, Simon Van Mulders, Cassandre Ekta Contré, Hartmut Zohm

Rapid inter-discharge simulation and optimization using the RAPTOR code have allowed the development of a reliable and reproducible early heating strategy for an advanced tokamak (AT) scenario on ASDEX Upgrade. Solving for electron heat and current diffusi ...

IOP Publishing Ltd2024

Scenario optimization for the tokamak ramp-down phase in RAPTOR. Part B: safe termination of DEMO plasmas

Olivier Sauter, Federico Alberto Alfredo Felici, Simon Van Mulders, Cassandre Ekta Contré, Emiliano Fable, Anna Teplukhina

An optimized plasma current ramp-down strategy is critical for safe and fast termination of plasma discharges in a tokamak demonstration fusion reactor (DEMO), both in planned and emergency scenarios, avoiding plasma disruptions and excessive heat loads to ...

Iop Publishing Ltd2024

Interpretative 3D MHD modelling of deuterium SPI into a JET H-mode plasma

Cristian Sommariva, Umar Sheikh, Mengdi Kong, Haomin Sun

The pre-thermal quench (pre-TQ) dynamics of a pure deuterium ( D 2 ) shattered pellet injection (SPI) into a 3 MA / 7 MJ JET H-mode plasma is studied via 3D non-linear MHD modelling with the JOREK code. The interpretative modelling captures the overall evo ...

IOP Publishing Ltd2024

Iterative removal of sources to model the turbulent electromotive force

Jennifer Waltraud Schober, Abhijit Bhausaheb Bendre

We describe a novel method to compute the components of dynamo tensors from direct magnetohydrodynamic (MHD) simulations. Our method relies upon an extension and generalization of the standard H & ouml;gbom CLEAN algorithm widely used in radio astronomy to ...

Oxford Univ Press2024

Global fluid simulations of plasma turbulence in stellarators

António João Caeiro Heitor Coelho

In order to cope with the decarbonization challenge faced by many countries, fusion is one of the few alternatives to fossil fuels for the production of electricity. Two devices invented in the middle of the previous century have emerged as the most promis ...

EPFL2024

FENNECS: a novel particle-in-cell code for simulating the formation of magnetized non-neutral plasmas trapped by electrodes of complex geometries

Stefano Alberti, Jean-Philippe Hogge, Joaquim Loizu Cisquella, Jérémy Genoud, Francesco Romano, Guillaume Michel Le Bars

This paper presents the new 2D electrostatic particle -in -cell code FENNECS developed to study the formation of magnetized non -neutral plasmas in geometries with azimuthal symmetry. This code has been developed in the domain of gyrotron electron gun desi ...

2024

Towards practical reinforcement learning for tokamak magnetic control

Federico Alberto Alfredo Felici, Cristian Galperti, Jonas Buchli, Brendan Tracey

Reinforcement learning (RL) has shown promising results for real-time control systems, including the domain of plasma magnetic control. However, there are still significant drawbacks compared to traditional feedback control approaches for magnetic confinem ...

Elsevier Science Sa2024

The effect of plasma shaping on high density H-mode SOL profiles and fluctuations in TCV

Holger Reimerdes, Benoît Labit, Christian Gabriel Theiler, Umar Sheikh, Guang-Yu Sun, Luke Simons, Nicola Vianello, Sophie Danielle Angelica Gorno, Cedric Kar-Wai Tsui, Claudia Colandrea, Adriano Stagni, Yi Wang

The impact of plasma shaping on the properties of high density H-mode scrape-off layer (SOL) profiles and transport at the outer midplane has been investigated on Tokamaka configuration variable. The experimental dataset has been acquired by evolving the u ...

IOP Publishing Ltd2024

Multi-machine benchmark of the self-consistent 1D scrape-off layer model DIV1D from stagnation point to target with SOLPS-ITER

Holger Reimerdes

This paper extends a 1D dynamic physics-based model of the scrape-off layer (SOL) plasma, DIV1D, to include the core SOL and possibly a second target. The extended model is benchmarked on 1D mapped SOLPS-ITER simulations to find input settings for DIV1D th ...

Iop Publishing Ltd2024

How accurate are flux-tube (local) gyrokinetic codes in modeling energetic particle effects on core turbulence?

Olivier Sauter, Alberto Bottino, Emanuele Poli

Flux-tube (local) gyrokinetic codes are widely used to simulate drift-wave turbulence in magnetic confinement devices. While a large number of studies show that flux-tube codes provide an excellent approximation for turbulent transport in medium-large devi ...

IOP Publishing Ltd2023

Chiral magnetohydrodynamics with zero total chirality

Kohei Kamada, Jennifer Waltraud Schober

We study the evolution of magnetic fields coupled with chiral fermion asymmetry in the framework of chiral magnetohydrodynamics with zero initial total chirality. The initial magnetic field has a turbulent spectrum peaking at a certain characteristic scale ...

American Physical Society2023

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

Decay law of magnetic turbulence with helicity balanced by chiral fermions

Kohei Kamada, Jennifer Waltraud Schober

In plasmas composed of massless electrically charged fermions, chirality can be interchanged with magnetic helicity while preserving the total chirality through the quantum chiral anomaly. The decay of turbulent energy in plasmas such as those in the early ...

AMER PHYSICAL SOC2023

Ultra long turbulent eddies, magnetic topology, and the triggering of internal transport barriers in tokamaks

Stephan Brunner, Justin Richard Ball, Arnas Volcokas

Local nonlinear gyrokinetic simulations of tokamak plasmas demonstrate that turbulent eddies can extend along magnetic field lines for hundreds of poloidal turns when the magnetic shear is very small. By accurately modeling different field line topologies ...

IOP Publishing Ltd2023

Gyrokinetic simulation of low-n Alfvenic modes in tokamak HL-2A plasmas

Javier García Hernández, Samuele Mazzi

The turbulence characteristics of plasmas with internal transport barriers in the HL-2A tokamak are analyzed by means of linear gyrokinetic simulations. It is found that turbulence is dominated by the ion temperature gradient (ITG) mode together with large ...

2023

Validation of GBS plasma turbulence simulation of the TJ-K stellarator

Paolo Ricci, Joaquim Loizu Cisquella

We present a validation of a three-dimensional, two-fluid simulation of plasma turbulence in the TJ-K stellarator, a low temperature plasma experiment ideally suited for turbulence measurements. The simulation is carried out by the GBS code, recently adapt ...

IOP Publishing Ltd2023

Exploration of the parameter space for the excitation and saturation of Edge Harmonic Oscillations

Guillermo Bustos Ramirez

This thesis presents advancements in the understanding of the plasma conditions leading to the excitation and saturation of the Edge Harmonic Oscillations (EHOs) observed during QH-mode operation in tokamak plasmas. Such operations represent a safer altern ...

EPFL2023