Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Concept

Onde d'Alfvén

Publications associées (30)

Oblique streaming waves observed in multipactor-induced plasma discharge above a dielectric surface

Guang-Yu Sun, Haomin Sun

In a recent discovery (Wen et al 2022 Phys. Rev. Lett. 129 045001), streaming waves were found in multipactor-induced plasma discharges. However, due to the limitations of a 1D simulation setup, these waves displayed only transverse dynamics. In this lette ...

2024

Nonlinear interaction of Alfvénic instabilities and turbulence via the modification of the equilibrium profiles

Laurent Villard, Alberto Bottino

Nonlinear simulations of Alfvén modes (AMs) driven by energetic particles (EPs) in the presence of turbulence are performed with the gyrokinetic particle-in-cell code ORB5. The AMs carry a heat flux, and consequently they nonlinearly modify the plasma temp ...

Cambridge University Press2023

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

Excitation of toroidal Alfvén eigenmodes with counter-current NBI in the TCV tokamak

Laurie Porte, Alexander Karpushov, Matteo Vallar, Samuele Mazzi

In TCV, unstable modes excited by resonant interaction between the shear Alfvèn waves in con- tinuum gaps and energetic particles have been observed in scenarios with Neutral Beam Injection (NBI). TCV is a middle-size device (R 0 /a = 0.88/0.25) equipped w ...

IOP Publishing Ltd2023

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

Olivier Sauter, Alberto Bottino

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

Dissipative magnetic structures and scales in small-scale dynamos

Salim Bennouna

Small-scale dynamos play important roles in modern astrophysics, especially on galactic and extragalactic scales. Owing to dynamo action, purely hydrodynamic Kolmogorov turbulence hardly exists and is often replaced by hydromagnetic turbulence. Understandi ...

OXFORD UNIV PRESS2023

Occam's razor on the mechanism of resistive-wall-mode-induced beta limits in diverted tokamaks

Jonathan Graves, Daniele Brunetti

External kink modes, believed to be the drive of the 0-limiting resistive wall mode, are strongly stabilized by the presence of a separatrix. We thus propose a novel mechanism explaining the appearance of long-wavelength global instabilities in free bounda ...

2023

Predictive modeling of Alfvén eigenmode stability in inductive scenarios in JT-60SA

Javier García Hernández, Antonio José Pereira de Figueiredo, Matteo Vallar

The JT-60SA device offers unique conditions before ITER for the study of the interaction of energetic particles with plasma waves. With similar dimensions to JET, e.g., a major radius but with a slightly more elongated plasma volume, JT-60SA is used as a h ...

Frontiers Media Sa2023

An analytical solution of the isentropic vortex problem in the special relativistic magnetohydrodynamics

Junming Duan

The isentropic vortex problem is frequently solved to test the accuracy of numerical methods and verify corresponding code. Unfortunately, its existing solution was derived in the relativistic magnetohydrodynamics by numerically solving an ordinary differe ...

ACADEMIC PRESS INC ELSEVIER SCIENCE2022

Production of a Chiral Magnetic Anomaly with Emerging Turbulence and Mean-Field Dynamo Action

Salim Bennouna

In relativistic magnetized plasmas, asymmetry in the number densities of left-and right-handed fermions, i.e., a nonzero chiral chemical potential mu(5), leads to an electric current along the magnetic field. This causes a chiral dynamo instability for a u ...

AMER PHYSICAL SOC2022

The Alfvenic nature of chromospheric swirls

Aleksi Antoine Bossart

Context. Observations show that small-scale vortical plasma motions are ubiquitous in the quiet solar atmosphere. They have received increasing attention in recent years because they are a viable candidate mechanism for the heating of the outer solar atmos ...

EDP SCIENCES S A2021

Interpretation of electromagnetic modes in the sub-TAE frequency range in JET plasmas with elevated monotonic q-profiles

Paulo Giovane Paschoali Pereira Puglia

Recent JET deuterium experiments with an advanced tokamak scenario using an internal transport barrier (ITB) have been performed to clearly observe destabilized toroidicity-induced Alfven eigenmodes (TAEs) by fast ions; interestingly, these also exhibit un ...

2021

Plasma heating and generation of energetic D ions with the 3-ion ICRF + NBI scenario in mixed H-D plasmas at JET-ILW

Henri Weisen, Javier García Hernández

Dedicated experiments were conducted in mixed H-D plasmas in JET to demonstrate the efficiency of the 3-ion ICRF scenario for plasma heating, relying on injected fast NBI ions as the resonant ion component. Strong core localization of the RF power depositi ...

IOP Publishing Ltd2020

Effect of periodic gas-puffs on drift-tearing modes in ADITYA/ADITYA-U tokamak discharges

Harshita Raj

The effect of a periodic train of short gas-puff pulses on the rotation frequency and amplitude of drift-tearing modes has been studied in ADITYA/ADITYA-U tokamak. The short gas puffs, injecting approximately similar to 10(17)-10(18) molecules of fuel gas ...

IOP Publishing Ltd2020

Chiral fermion asymmetry in high-energy plasma simulations

Salim Bennouna

The chiral magnetic effect (CME) is a quantum relativistic effect that describes the appearance of an additional electric current along a magnetic field. It is caused by an asymmetry between the number densities of left- and right-handed fermions, which ca ...

2020

Effect of the tangential NBI current drive on the stability of pressure and energetic particle driven MHD modes in LHD plasma

Wilfred Anthony Cooper

The aim of the present study is to analyze the stability of the pressure gradient driven modes (PM) and Alfven eigenmodes (AE) in the large helical device (LHD) plasma if the rotational transform profile is modified by the current drive of the tangential n ...

IOP Publishing Ltd2020

Kinetic-MHD stability of virtually collisionless plasmas

Samuel Lanthaler

The stability of pressure driven modes such as the 1/1 internal kink is known to depend sensitively on a multitude of physical effects such as toroidal rotation, kinetic effects due to thermal and suprathermal particle species and finite Larmor radius effe ...

EPFL2020

Time intermittency in nondiffusive transport regimes of suprathermal ions in turbulent plasmas

Ambrogio Fasoli, Ivo Furno, Paolo Ricci, Marcelo Baquero Ruiz, Oulfa Chellaï, Fabian Manke

Intermittent phenomena have long been studied in the context of nondiffusive transport across a variety of fields. In the TORPEX device, the cross-field spreading of an injected suprathermal ion beam by electrostatic plasma turbulence can access different ...

AMER PHYSICAL SOC2019

Projective multiscale time-integration for electrostatic particle-in-cell methods

Jan Sickmann Hesthaven, Paul Isaac Denis Louis Marie Cazeaux

The simulation of problems in kinetic plasma physics is often challenging due to strongly coupled phenomena across multiple scales. In this work, we propose a wavelet-based coarse-grained numerical scheme, based on the framework of Equation-Free Projective ...

2019

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

Yiming Li, Olivier Sauter, Richard Pitts, Ambrogio Fasoli, Basil Duval, Henri Weisen, Yann Camenen, Jan Horacek, Javier García Hernández, Duccio Testa, Marco Wischmeier, Nicola Vianello, Mikhail Maslov, Patrick Blanchard, Alessandro Pau, Davide Galassi, Federico Alberto Alfredo Felici, Antonio José Pereira de Figueiredo, Cristian Sommariva, Jonathan Graves, Emiliano Fable, Francesca Maria Poli, Antoine Pierre Emmanuel Alexis Merle, Federico Nespoli, Daniele Brunetti, Anna Teplukhina, Hamish William Patten, Samuel Lanthaler, Haomin Sun, Alberto Mariani, Michele Marin

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