Publications associées à Héliosphère

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

Small-scale dynamo with finite correlation times

Jennifer Waltraud Schober

Fluctuation dynamos occur in most turbulent plasmas in astrophysics and are the prime candidates for amplifying and maintaining cosmic magnetic fields. A few analytical models exist to describe their behavior, but they are based on simplifying assumptions. ...

AMER PHYSICAL SOC2023

Solar Wind Protons in the Diamagnetic Cavity at Comet 67P/Churyumov-Gerasimenko

Lucie Anemone Scharré

The plasma environment at a comet can be divided into different regions with distinct plasma characteristics. Two such regions are the solar wind ion cavity, which refers to the part of the outer coma that does not contain any solar wind ions anymore; and ...

AMER GEOPHYSICAL UNION2023

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

Jennifer Waltraud Schober

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

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, Roberto Maurizio, Davide Galassi, Cedric Kar-Wai Tsui, 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 ...

IOP Publishing Ltd2021

Development of a real-time algorithm for detection of the divertor detachment radiation front using multi-spectral imaging

Christian Gabriel Theiler, Artur Perek, Kevin Henricus Annemarie Verhaegh, Wouter Vijvers

In this paper we present a novel algorithm to extract the optical plasma boundary and radiation front for detached divertor plasmas. We show that reliable detection of the divertor leg and radiation front is possible using lightweight image processing tool ...

IOP Publishing Ltd2020

Characterizing time intermittency in non-diffusive fast ion transport through plasma turbulence

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

Turbulent fast ion transport has been investigated in astrophisycal, laboratory and fusion plasmas. When gyro- and drift-averaging across plasma structures manifest as non-markovian and non-local effects, this results in generally non-diffusive transport. ...

IOP PUBLISHING LTD2020

Modeling of TAE mode excitation with an antenna in realistic X-point geometry

Ambrogio Fasoli, Duccio Testa

Experimentally, it is observed that Toroidal Alfven Eigenmodes (TAEs) are difficult to excite with an external antenna when the plasma is in X-point geometry. Here, the effect of the X-point geometry on the efficiency of the TAE excitation with the externa ...

AMER INST PHYSICS2020

Voyager 2 plasma observations of the heliopause and interstellar medium

Paula Garcia Galindo

The solar wind blows outwards from the Sun and forms a bubble of solar material in the interstellar medium. The heliopause (HP) is the boundary that divides the hot tenuous solar wind plasma in the heliosheath from the colder, denser very local interstella ...

NATURE PUBLISHING GROUP2019

A wall-aligned grid generator for non-linear simulations of MHD instabilities in tokamak plasmas

Olivier Sauter, Ambrogio Fasoli, Basil Duval, Stefano Coda, Jonathan Graves, Yves Martin, Duccio Testa, Patrick Blanchard, Henri Weisen, Alessandro Pau, Mikhail Maslov, Cristian Sommariva, Federico Nespoli, Richard Pitts, David Pfefferlé, Yann Camenen, Jonathan Marc Philippe Faustin, Jan Horacek, Hamish William Patten, Javier García Hernández, Samuel Lanthaler, Marco Wischmeier, Nicola Vianello, Yao Zhou, Davide Galassi, Antonio José Pereira de Figueiredo, Liang Yao, Dalziel Joseph Wilson, Bernhard Sieglin, Otto Asunta

Block-structured mesh generation techniques have been well addressed in the CFD community for automobile and aerospace studies, and their applicability to magnetic fusion is highly relevant, due to the complexity of the plasma-facing wall structures inside ...

ELSEVIER2019

Molecular clouds in the Cosmic Snake normal star-forming galaxy 8 billion years ago

Jean-Paul Richard Kneib, Daniel Pfenniger, Johan Richard

The cold molecular gas in contemporary galaxies is structured in discrete cloud complexes. These giant molecular clouds (GMCs), with 10(4)-10(7) solar masses (M-circle dot) and radii of 5-100 parsecs, are the seeds of star formation(1). Highlighting the mo ...

NATURE PUBLISHING GROUP2019

Millimeter-wave beam scattering by edge-plasma density fluctuations in TCV

Stefano Alberti, Timothy Goodman, Oulfa Chellaï, Ivo Furno, Fabio Riva, Paolo Ricci, Benoît Labit, Marcelo Baquero Ruiz, Emanuele Poli

In magnetically confined fusion devices, the use of millimeter waves (mmw) at the electron cyclotron (EC) frequencies ranges from plasma diagnostics to plasma heating, current drive and core confinement preservation. For large tokamaks such as ITER, numeri ...

2019

Two-fluid solutions for Langmuir probes in collisionless and isothermal plasma, over all space and bias potential

Ivo Furno, Alan Howling, Philippe Frédérique Bruno Guittienne

This paper presents solutions for the classical one-dimensional (1D radial and Cartesian) problem of Langmuir probes in a collisionless, isothermal plasma. The method is based on two-fluid equations derived from the first two moments of Vlasov's equation. ...

2018

An arbitrary wavelength solver for global gyrokinetic simulations. Application to the study of fine radial structures on microturbulence due to non-adiabatic passing electron dynamics

Laurent Villard, Stephan Brunner, Trach-Minh Tran, Ben McMillan, Gabriele Merlo, Julien Stanislas Pierre Dominski

The influence of the fine layers of the non-adiabatic passing electron response on electrostatic turbulent transport, previously studied systematically in flux tube geometry [Dominski et al., Phys. Plasmas 22, 062303 (2015)], is pursued in global geometry ...

Amer Inst Physics2017

Three-dimensional magnetohydrodynamic equilibrium of quiescent H-modes in tokamak systems

Olivier Sauter, Basil Duval, Jonathan Graves, Wilfred Anthony Cooper, Trach-Minh Tran, Jonathan Marc Philippe Faustin, Hamish William Patten, Samuel Lanthaler, Madhusudan Raghunathan, Andreas Kleiner

Three dimensional free boundary magnetohydrodynamic equilibria that recover saturated ideal kink/peeling structures are obtained numerically. Simulations that model the JET tokamak at fixed = 1.7% with a large edge bootstrap current that flattens t ...

IOP Publishing2016

Development and application of Eulerian and Particle-in-Cell gyrokinetic codes for studying the effect of non-adiabatic passing electron dynamics on microturbulence

Julien Stanislas Pierre Dominski

In tokamak fusion plasmas, micro-turbulence transport is known to be the cause of large losses of heat and particles. The present work deals with the study of electrostatic micro-turbulence transport driven by instabilities of essentially two types: the io ...

EPFL2016

Superdiffusive transport in laboratory and astrophysical plasmas

Ambrogio Fasoli, Ivo Furno, Paolo Ricci, Kyle Gustafson, Alexandre Dominique Bovet

In the last few years it has been demonstrated, both by data analysis and by numerical simulations, that the transport of energetic particles in the presence of magnetic turbulence can be superdiffusive rather than normal diffusive (Gaussian). The term ‘su ...

Cambridge University Press2015

Improved confinement in high-density H-modes via modification of the plasma boundary with lower hybrid waves

Christian Gabriel Theiler, Yu Lin, Peng Xu

Injecting Lower Hybrid Range of Frequency (LHRF) waves into Alcator C-Mod's high-density H-mode plasmas has led to enhanced global energy confinement by increasing pedestal temperature and pressure gradients, decreasing the separatrix density, modifying th ...

Amer Inst Physics2015

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

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

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

Real-time optical plasma boundary reconstruction for plasma position control at the TCV Tokamak

Basil Duval, Yanis Andrebe, Hoang Bao Le

A dual, high speed, real-time visible light camera setup was installed on the TCV tokamak to reconstruct optically and in real-time the plasma boundary shape. Localized light emission from the plasma boundary in tangential view, broadband visible images re ...

IOP Publishing Ltd2014