Publications associées à RF current drive and plasma fluctuations

Exploiting the Signal-Leak Bias in Diffusion Models

Sabine Süsstrunk, Radhakrishna Achanta, Mahmut Sami Arpa, Athanasios Fitsios, Martin Nicolas Everaert

There is a bias in the inference pipeline of most diffusion models. This bias arises from a signal leak whose distribution deviates from the noise distribution, creating a discrepancy between training and inference processes. We demonstrate that this signa ...

2024

Global existence for perturbations of the 2D stochastic Navier-Stokes equations with space-time white noise

Martin Hairer

We prove global in time well-posedness for perturbations of the 2D stochastic Navier-Stokes equations partial derivative( t)u + u center dot del u = Delta u - del p + sigma + xi, u(0, center dot ) = u(0),div (u) = 0, driven by additive space-time white noi ...

Springernature2024

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

Integrated Wireless Power, Data Communication, and Thermal Sensing System for Autonomous Multisite Brain Implants

Implanted medical devices (IMDs) have been widely developed to support the monitoring and recording of biological data inside the body or brain. Wirelessly powered IMDs, a subset of implantable electronics, have been proposed to eliminate the limitations r ...

EPFL2024

Spectral Estimators for High-Dimensional Matrix Inference

Farzad Pourkamali

A key challenge across many disciplines is to extract meaningful information from data which is often obscured by noise. These datasets are typically represented as large matrices. Given the current trend of ever-increasing data volumes, with datasets grow ...

EPFL2024

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

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

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

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

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

A model of non-Maxwellian electron distribution function for the analysis of ECE data in JET discharges

Mikhail Maslov, Javier García Hernández, Samuele Mazzi

Recent experiments performed in JET at high level of plasma heating, in preparation of, and during the DT campaign have shown significant discrepancies between electron temperature measurements by Thomson Scattering (TS) and Electron Cyclotron Emission (EC ...

E D P SCIENCES2023

Modelling of nonneutral plasmas trapped by electric and magnetic fields relevant to gyrotron electron guns

Guillaume Michel Le Bars

Gyrotrons are a class of high-power vacuum-electronics microwave sources, which are envisioned to play an important role in the domain of magnetically confined fusion plasmas. Indeed, only gyrotrons are capable of producing continuous electromagnetic waves ...

EPFL2023

Measuring the electron energy distribution in tokamak plasmas from polarized electron cyclotron radiation

Arsène Stéphane Tema Biwole

In this doctoral thesis, a promising technique has been used for the measurement of non-thermal electrons in TCV. The technique employs a Vertical viewing ECE to more easily discriminate the radiation according to the energy of the electrons. Successful ...

EPFL2023

Studies on EU-DEMO 3D coils requirements and conceptual design for error field correction and plasma control

Pierluigi Bruzzone, Hartmut Zohm, Leonardo Pigatto

This work presents the initial studies on the requirements for the design of 3D coils on EU-DEMO. The use of 3D coils in present machines includes two main purposes: the first one is the Error Field Correction (EFC). The EFC aims at minimizing the intrinsi ...

Elsevier Science Sa2023

Experimental and numerical investigations of electron transport enhancement by electron-cyclotron plasma-wave interaction in tokamaks

Laurent Villard, Stefano Coda, Laurie Porte, Joan Decker, Aylwin Iantchenko, Jean Arthur Cazabonne, Giovanni Di Giannatale

Energy transfer from electron-cyclotron (EC) waves to the plasma is being routinely used in tokamaks to heat and drive current through the electron channel. Technical applications such as magnetohydrodynamic mode mitigation require power deposition with a ...

IOP Publishing Ltd2023

Nanomechanical resonators with low dissipation for quantum optomechanics

Alberto Beccari

Fields of technology as diverse as microwave filter construction, characterization of material interfaces with atomic precision, and detection of gravitational waves from astronomical sources employ mechanical resonators at their core. The utility of mecha ...

EPFL2023

SoDaCam: Software-defined Cameras via Single-Photon Imaging

Claudio Bruschini, Edoardo Charbon, Andrei Ardelean, Mohit Gupta

Reinterpretable cameras are defined by their post-processing capabilities that exceed traditional imaging. We present "SoDaCam" that provides reinterpretable cameras at the granularity of photons, from photon-cubes acquired by single-photon devices. Photon ...

Ieee Computer Soc2023

A synthetic phase-contrast imaging diagnostic with spatial filtering for gyrokinetic simulations

Stephan Brunner, Stefano Coda, Gabriele Merlo, Aylwin Iantchenko, Justin Richard Ball

A Phase-contrast imaging (PCI) diagnostic provides measurements of line-integrated electron density fluctuations. Localisation along the laser beam path can be achieved with a spatial filter that selects the wave-vector directions of the fluctuations contr ...

2023

Characterization of transversely confined electron beam-generated plasma using two-dimensional particle-in-cell simulations

Guang-Yu Sun, Haomin Sun

Electron beam-generated plasmas (EBPs) have been used to modify the surface properties. In certain applications, EBPs are transversely confined and their properties are of value to the treatment. In this paper, the characteristics of an electron beam-gener ...

American Institute of Physics (AIP)2023

Disentangling 1/f noise from confined ion dynamics

Théo Denis Tobias Emmerich

Ion transport through biological and solid-state nanochannels is known to be a highly noisy process. The power spectrum of current fluctuations is empirically known to scale like the inverse of frequency, following the long-standing yet poorly understood H ...

ROYAL SOC CHEMISTRY2023

Plasma sputtering of biased electrodes in an oblique magnetic field

Stefano Alberti, Ivo Furno, Alessandro Geraldini

The surface erosion of biased electrodes immersed in a radio frequency (RF) plasma was investigated in oblique magnetic fields ranging from 0.1 T to 3.5 T. The plasma potential and density in the vicinity of the biased electrode have been measured using an ...

IOP Publishing Ltd2023

An Unbiased Method of Measuring the Ratio of Two Data Sets

Jean-Paul Richard Kneib, Huanyuan Shan

In certain cases of astronomical data analysis, the meaningful physical quantity to extract is the ratio R between two data sets. Examples include the lensing ratio, the interloper rate in spectroscopic redshift samples, and the decay rate of gravitational ...

IOP Publishing Ltd2023

Universal and adaptive methods for robust stochastic optimization

Ali Kavis

Within the context of contemporary machine learning problems, efficiency of optimization process depends on the properties of the model and the nature of the data available, which poses a significant problem as the complexity of either increases ad infinit ...

EPFL2023