Publications associées à Ceinture de Van Allen

Direct observations of X-rays produced by upward positive lightning

Marcos Rubinstein, Antonio Sunjerga, Farhad Rachidi-Haeri, Thomas Chaumont

X-rays have been observed in natural downward cloud-to-ground lightning for over 20 years and in rocket-triggered lightning for slightly less. In both cases, this energetic radiation has been detected during the stepped and dart leader phases of downward n ...

Nature Publishing Group2024

The X-Point radiating regime at ASDEX Upgrade and TCV

Holger Reimerdes, Christian Gabriel Theiler, Marco Wischmeier, Umar Sheikh, Artur Perek, Bernhard Sieglin

Future fusion reactors require a safe, steady-state divertor operation. With deep divertor detachment, which is typically induced by impurity seeding, the radiation concentrates in a small region at the X-point or on closed flux surfaces above the X-point. ...

Elsevier2023

The Alfvenic nature of chromospheric swirls

Aleksi Antoine Bossart, Andrea Francesco Battaglia

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

Development of free-boundary equilibrium and transport solvers for simulation and real-time interpretation of tokamak experiments

Francesco Carpanese

To exploit fusion as a source of energy, a hot and dense confined plasma is needed. This is achieved in tokamaks by actively controlling the plasma state meaning shape, position and internal kinetic profiles. This thesis addresses two topics: the developme ...

EPFL2021

Design and Numerical Analyses of the M4 Steering Mirrors for the ITER Electron Cyclotron Heating Upper Launcher

Timothy Goodman, René Chavan, Matteo Vagnoni, Avelino Mas Sanchez

Four electron cyclotron heating upper launchers (ECHULs) will be used at ITER to counteract magnetohydrodynamic plasma instabilities by targeting them with up to 24 MW of mm-wave power at 170 GHz. This mm-wave power is injected through eight ex-vessel (EV) ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2019

Stochastic modeling of snow transport and hydrologic response in alpine terrain

Francesco Comola

The scientific community has developed a keen interest in the processes driving the hydrologic cycle in alpine regions. The concern mainly stems from the vulnerability of snow-covered environments to the warming temperatures, such that entire ecological an ...

EPFL2017

Scale-dependent effects of solar radiation patterns on the snow-dominated hydrologic response

Andrea Rinaldo, Michael Lehning, Bettina Schaefli, Francesco Comola, Mathias Thierry Pierre Bavay, Gianluca Botter, Pierfrancesco Da Ronco

Solar radiation is a dominant driver of snowmelt dynamics and streamflow generation in alpine catchments. A better understanding of how solar radiation patterns affect the hydrologic response is needed to assess when calibrated temperature-index models are ...

American Geophysical Union2015

Methylammonium Lead Iodide for Efficient X-ray Energy Conversion

László Forró, Endre Horvath, Bálint Náfrádi

We report on photocurrent generation by X-ray irradiation in methylammonium lead iodide CH3NH3PbI3 single crystals. We observed 75% of charge collection efficiency in millimeter sized samples. This efficiency is partially due to the high photon absorption ...

American Chemical Society2015

Visualizing street orientation and solar radiation in relation to complex topography

Jean-Louis Scartezzini, Jérôme Henri Kämpf, Nahid Mohajeri Pour Rayeni

Street networks can be visualized in various ways depending on the purpose. Here we introduce (in the present context) a new technique for visualizing the orientation of street networks in relation to complex topography. The technique is tested on the city ...

EuroGraphics Digital Library2014

Radiation hardness of high-Q silicon nitride microresonators for space compatible integrated optics

Tobias Kippenberg, Victor Brasch

Integrated optics has distinct advantages for applications in space because it integrates many elements onto a monolithic, robust chip. As the development of different building blocks for integrated optics advances, it is of interest to answer the importan ...

Optical Soc Amer2014

Measurement of edge electrostatic turbulence in the TCV tokamak plasma boundary

Jan Horacek

Almost since the first density profile measurements were made in the scrape-off layer (SOL) of the early tokamaks, it has been recognized that the rate of particle transport perpendicular to magnetic surfaces exceeds that expected on the basis of classical ...

EPFL2006