Concept

Solar dynamo

Related publications (19)

Comparison of filament properties in real-size GBS simulations and experiments of TCV-X21

A direct quantitative comparison of Scrape-Off Layer (SOL) filament properties obtained from fluid turbulence simulations with the GBS code and from experiments on the TCV tokamak is performed within the TCV-X21 validation case. This comparison is made possible by extending the open TCV-X21 dataset with 2-D turbulence measurements obtained with Gas Puff Imaging (GPI), providing critical information on the size, velocity, and other key characteristics of turbulent filaments at the outboard midplane and in th

IOP Publishing2026

Investigation of finite aspect ratio effects in axisymmetric magnetic equilibria with toroidal rotation and pressure anisotropy

The inverse equilibrium formulation and numerical code described in [L.L. Lao Phys. Fluids 24, 1431–1440 (1981)] are extended in a new `exact' fixed boundary equilibrium code that accounts for plasma toroidal rotation and pressure anisotropy. The formulation precisely captures deviations from an inverse aspect ratio

\epsilon:=a/R_0

expansion, at various orders, with

a

a minor radius and

R_0

the major radius at the magnetic axis. We show that for experimentally relevant elongation

\kappa\lesssim 2

IOP Publishing2026

Radiation damage to the Hubble Space Telescope during two Solar cycles, and correction of Charge Transfer Inefficiency using ArCTIc

From 2002 to 2025, the Hubble Space Telescope’s Advanced Camera for Surveys has suffered in the harsh radiation environment above the protection of the Earth’s atmosphere. We track the degradation of its image quality, as Solar protons and galactic cosmic rays have damaged its photosensitive charge-coupled device (CCD) imaging sensors. The rate of damage in low Earth orbit is modulated by

18.5^{+4.5}_{-0.5}

per cent during an 11 year Solar cycle, peaking

430^{+11}_{-5}

days after Solar minimum as record

Oxford University Press (OUP)2025

Global risks of renewable energy droughts under climate change

Addressing climate change and reducing greenhouse gas emissions requires integrating variable renewable energy sources, such as solar and wind, into national energy systems. However, periods of compounding low wind and solar potential, known as energy droughts or ‘Dunkelflaute’ conditions, present significant challenges for electricity grids. While some regional studies on energy droughts exist, there is no comprehensive global assessment of how future climate changes might affect these events. Using temper

2025

Turbulence simulations in diverted geometry

The study of scrape-off layer (SOL) is a fundamental step in magnetic confinement fusion research. For example, SOL sets the boundary conditions for the tokamak core and it provides the energy flux toward the tokamak wall. With the goal of improving our understanding of the SOL dynamics, the GBS code was developed during the past years. GBS simulates the SOL turbulence by solving the drift-reduced Braginskii equations for the two-fluid model of the plasma. In this work, the simulations are performed by cons

2018

Geometric formulas for system codes including the effect of negative triangularity

Olivier Sauter

Formulas for the volume, poloidal and toroidal surfaces, poloidal length, plasma current, and hence average poloidal field, are determined using global parameters of tokamak plasmas. Previous formulas did not include systematically the effect of triangular ...

Elsevier2016

Basic characterization of TORPEX electrostatic modes in closed field line configurations

Ambrogio Fasoli, Ivo Furno, Paolo Ricci, Fabio Avino, Sébastien Jolliet

Electrostatic coherent modes are studied in the TORPEX device [Fasoli et al., Plasma Phys. Controlled Fusion 52, 124020 (2010)], in closed flux surfaces. The accessibility to this magnetic geometry is provided by a current-carrying in-vessel toroidal condu ...

Amer Inst Physics2014

Optimization of experimental snowflake configurations on TCV

Stefano Coda, Jean-Marc Moret, Holger Reimerdes

The design of a snowflake (SF) equilibrium requires a strong effort on the poloidal field (PF) currents in terms of MAturns and mechanical loads. This has limited the maximum plasma current in SF configurations on Tokamak a Configuration Variable (TCV) to ...

International Atomic Energy Agency2014

Plasma turbulence in the tokamak scrape-off layer

In the tokamak scrape-off layer (SOL) the magnetic field lines are open, channeling particles and heat onto plasma facing components, and constraining their lifetime. This is a critical issue for ITER and future devices -- safe operation of fusion devices will require a better understanding of the SOL plasma dynamics \cite{Loarte2007}. The steady-state heat load onto the tokamak plasma facing components depends on the SOL width, which results from a balance between plasma injection from the core region, tur

2014

Plasma turbulence studies in TORPEX basic plasma pyhsics device: from concentric flux surfaces to single null X-points

TORPEX is a basic plasma physics device where a simple magnetized torus (SMT) is produced by adding a small vertical magnetic field to a main toroidal component, generating helical field lines. The SMT configuration features the main ingredients of a tokamak Scrape-Off Layer (SOL), namely density gradients in the presence of magnetic field curvature and gradient. Recently, a toroidal in-vessel copper conductor has been installed in the TORPEX device. A current up to 1kA can be driven in the toroidal conduct

2014

Analysis of global hydromagnetic instabilities driven by strongly sheared toroidal flows in tokamak plasmas

Jonathan Graves

Recent numerical calculations have shown that while strong toroidal rotation can increase the external kink limit of tokamak plasmas, the associated rotation shear can drive a Kelvin-Helmholtz like global instability in the plasma, if the rotation frequenc ...

Iop Publishing Ltd2013

Study of plasma fluctuations in new closed flux-surface configurations of the TORPEX experiment

Ambrogio Fasoli, Ivo Furno

The TORoidal Plasma EXperiment (TORPEX) is a Simple Magnetized Torus (SMT) where open helical magnetic field lines are obtained from the superposition of a small vertical component on the main toroidal field. The SMT configuration features the main driving mechanisms of plasma instabilities characterising the Scrape-Off Layer (SOL) of larger tokamak devices, making TORPEX a very attractive machine to perform fusion oriented studies of plasma turbulence. A new experimental set-up has been recently developed

2013

Observations on turbulence and beam-ion driven modes in TEXTOR

Stefano Coda, Mattia Albergante, Cornelis Adrianus de Meijere

At a sufficiently weak toroidal magnetic field, neutral beam injection heated, limited plasmas in the TEXTOR tokamak exhibit bursts of beam-ion driven 'fishbone' and Alfven modes, which are characterized for the first time using the multi-antenna reflectom ...

Iop Publishing Ltd2012

Indirect measurement of poloidal rotation using inboard–outboard asymmetry of toroidal rotation and comparison with neoclassical predictions

Olivier Sauter, Basil Duval, Alexander Karpushov, Yanis Andrebe, Yann Camenen, Alessandro Bortolon, Lucia Isabel Federspiel

An alternative experimental spectroscopic measurement of poloidal plasma rotation in toroidally confined plasmas is proven effective in the TCV tokamak. Charge exchange recombination measurements of the toroidal rotation profile over the full mid-plane pla ...

Int Atomic Energy Agency2012

The effects of sheared toroidal rotation on stability limits in tokamak plasmas

Jonathan Graves

Sheared toroidal rotation is found to increase the ideal external kink stability limit, thought to be the ultimate performance limit in fusion tokamaks. However, at rotation speeds approaching a significant fraction of the Alfv´en speed, the toroidal rotat ...

2011

Transport studies in the snowflake divertor in TCV

The transport of heat and particles in a tokamak plasma with a snowflake divertor has been studied in recent TCV experiments. Estimates of the power flux onto the divertor plates are obtained from measurements with multiple infrared cameras and Langmuir probes. The studies include L- and ELMy H-mode plasmas and confirm some of the advantageous properties of the snowflake configuration, such as the distribution of the exhaust power on more strike points than the two that characterize conventional divertor co

2011

SOLPS modelling of ELMing H-mode

Barbora Bruant Gulejová

Numerical simulation of the tokamak scrape-off layer (SOL) is an essential tool for the prediction of the conditions to be expected in future fusion reactors such as the ITER project, now under construction in Southern France. One particularly important is ...

EPFL2010

Saturated ideal modes in advanced tokamak regimes in MAST

Jonathan Graves

MAST plasmas with a safety factor above unity and a profile with either weakly reversed shear or broad low-shear regions, regularly exhibit long-lived saturated ideal magnetohydrodynamic (MHD) instabilities. The toroidal rotation is flattened in the presen ...

IOP Publishing Ltd2010

Plasma rotation and momentum transport studies in the TCV tokamak based on charge exchange spectroscopy measurements

Alessandro Bortolon

Thermonuclear controlled fusion research is a highly active branch of plasma physics. The main goal is the production of energy from the fusion reaction of hydrogen isotope nuclei, the same reaction that powers stars. The most promising present approach ar ...

EPFL2009

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