Concept

Matrice triangulaire

Publications associées (122)

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An experimental and computational study of tokamak plasma turbulence

Aylwin Iantchenko

Turbulence driven by small-scale instabilities results in strong heat and particle transport, which significantly shortens the confinement time and prevents the formation of a self-sustained plasma reaction in magnetic confinement devices. Control and poss ...

EPFL2023

Modelling of sawtooth-induced fast ion transport in positive and negative triangularity in TCV

Olivier Sauter, Basil Duval, Duccio Testa, Alexander Karpushov, Mario Ludovico Podesta, Antoine Pierre Emmanuel Alexis Merle, Marcelo Baquero Ruiz, Dmytry Mykytchuk, Matteo Vallar, Lorenzo Stipani

Internal kinks are a common magneto hydro-dynamic (MHD) instability observed in tokamak operation when the q profile in the plasma core is close to unity. This MHD instability impacts both the transport of the bulk plasma (current, particle and energy tran ...

IOP Publishing Ltd2022

Iterative refinement of Schur decompositions

Daniel Kressner, Zvonimir Bujanovic

The Schur decomposition of a square matrix A is an important intermediate step of state-of-the-art numerical algorithms for addressing eigenvalue problems, matrix functions, and matrix equations. This work is concerned with the following task: Compute a (m ...

SPRINGER2022

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The favorable confinement properties of negative-triangularity (NT) tokamak configurations were discovered in the TCV tokamak in the late 1990s and were documented over the two following decades, through investigations of predominantly electron-heated plas ...

IOP Publishing Ltd2022

Matrix product states with backflow correlations

Giuseppe Carleo

By taking inspiration from the backflow transformation for correlated systems, we introduce a tensor network Ansatz which extends the well-established matrix product state representation of a quantum many-body wave function. This structure provides enough ...

AMER PHYSICAL SOC2022

IMPROVED VARIANTS OF THE HUTCH plus plus ALGORITHM FOR TRACE ESTIMATION

Daniel Kressner, Ulf David Persson, Alice Cortinovis

This paper is concerned with two improved variants of the Hutch++ algorithm for estimating the trace of a square matrix, implicitly given through matrix-vector products. Hutch++ combines randomized low-rank approximation in a first phase with stochastic tr ...

SIAM PUBLICATIONS2022

Study of impurity ion transport using charge exchange spectroscopy on TCV

Filippo Bagnato

The study of impurity transport in fusion plasmas has gained interest over the years due to its implication with tokamak performances. In TCV (Tokamak à Configuration Variable), as in many other facilities, impurity ions can be studied through the CXRS (Ch ...

EPFL2022

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Nuclear fusion using magnetic confinement, in particular in the tokamak configuration, is a promising path towards sustainable energy. A core challenge is to shape and maintain a high-temperature plasma within the tokamak vessel. This requires high-dimensi ...

2022

We establish a direct connection between general tensor networks and deep feed-forward artificial neural networks. The core of our results is the construction of neural-network layers that efficiently perform tensor contractions and that use commonly adopt ...

AMER PHYSICAL SOC2022

Diverted negative triangularity plasmas on DIII-D: the benefit of high confinement without the liability of an edge pedestal

Stefano Coda, Alessandro Marinoni, Francesco Sciortino

Diverted discharges at negative triangularity on the DIII-D tokamak sustain normalized confinement and pressure levels typical of standard H-mode scenarios (H (98y2) similar or equal to 1, beta (N) similar or equal to 3) without developing an edge pressure ...

IOP Publishing Ltd2021