Publications related to Dynamo

The effect of pressure-anisotropy-driven kinetic instabilities on magnetic field amplification in galaxy clusters

Context. The intracluster medium (ICM) is the low-density diffuse gas that fills the space between galaxies within galaxy clusters. It is primarily composed of magnetized plasma, which reaches virial temperatures of up to 10(8) K, probably due to mergers o ...

Edp Sciences S A2024

Shedding light on the MRI-driven dynamo in a stratified shearing box

Abhijit Bhausaheb Bendre

We study the magneto-rotational instability (MRI) dynamo in a geometrically thin disc (H/R < 1) using stratified zero net (vertical) flux shearing box simulations. We find that mean fields and electromotive forces (EMFs) oscillate with a primary frequency ...

2024

Dissipative magnetic structures and scales in small-scale dynamos

Jennifer Waltraud Schober

Small-scale dynamos play important roles in modern astrophysics, especially on galactic and extragalactic scales. Owing to dynamo action, purely hydrodynamic Kolmogorov turbulence hardly exists and is often replaced by hydromagnetic turbulence. Understandi ...

OXFORD UNIV PRESS2023

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

Modeling and Design Optimization of Loosely Coupled PCB Spiral Coils in Inductive Power Transfer Systems

Drazen Dujic, Xiaotong Du

There are various possibilities to realize coil winding designs for an inductive power transfer system. In order to achieve high power transfer efficiency and power density and explore trade-offs between the two, design optimization around the coil link is ...

2023

Diffusion-Bonding Between Strands and Modeling of Splices of Nb3Sn Rutherford Cables

Pierluigi Bruzzone, Kamil Sedlák, Nikolay Bykovskiy

Particle accelerators foresee the use of Nb3Sn in the next generation of dipole magnets. A common design strategy is to grade the coil, i.e., to optimize the quantity of superconductor in the turns with respect to the magnetic field intensity. As a consequ ...

IEEE Institute of Electrical and Electronics Engineers2022

Torque Computation With the Isogeometric Mortar Method for the Simulation of Electric Machines

Rafael Vazquez Hernandez, Bernard Kapidani

In this work, isogeometric mortaring is used for the simulation of a six-pole permanent magnet synchronous machine. Isogeometric mortaring is especially well suited for the efficient computation of rotating electric machines, as it allows for an exact geom ...

Institute of Electrical and Electronics Engineers2022

Inductive Power Transfer System for Auxiliary Power Supply in Medium Voltage Converters

Drazen Dujic, Chengmin Li, Xiaotong Du

Inductive power transfer technology is an attractive solution for medium voltage applications by eliminating the need for high voltage cables or wired connections in general. This paper introduces an inductive power transfer system which has multiple indep ...

2022

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

Experimental Investigation of a Small-Scale Organic Rankine Cycle Turbo-Generator Supported on Gas-Lubricated Bearings

Jürg Alexander Schiffmann, Kévin Rosset

Waste heat recovery (WHR) is expected to contribute to reducing CO2 emissions from trucks. Organic Rankine cycle (ORC) systems show the highest potential for this application, but still lack efficient small-scale expansion devices, in practice. A novel tur ...

2021

Small-scale organic Rankine cycle turbo-generator for waste heat recovery on truck engine

Kévin Rosset

Truck engine waste heat recovery (WHR) systems have been investigated for many years. Among them, organic Rankine cycle (ORC) systems show the highest potential, but still lack efficient small-scale expansion devices, in practice. Proposed expanders are of ...

EPFL2020

Small scale very high speed slotless permanent magnet motors

Guillaume Paul-André Burnand

This research work has been triggered by an industrial project aimed at modelling and manufacturing a small-scale very high speed motor. Very high speed electrical motors offer the main advantage of reducing the size of a system. Indeed, at constant output ...

EPFL2020

Chiral fermion asymmetry in high-energy plasma simulations

Jennifer Waltraud Schober

The chiral magnetic effect (CME) is a quantum relativistic effect that describes the appearance of an additional electric current along a magnetic field. It is caused by an asymmetry between the number densities of left- and right-handed fermions, which ca ...

2020

Very-High-Speed Miniaturized Permanent Magnet Motors: Modeling and Experimental Validation

Yves Perriard, Guillaume Paul-André Burnand

The purpose of this paper is to present an experimental method to separate losses components due to the rotation of the rotor in very-high-speed permanent magnet machines with ball bearings. In addition, it presents and validates an analytical model for th ...

2019

Electrical effects in winding of large electrical ac machines application to advanced large size DFIM

Frédéric Michael Maurer

To meet the electrical grid's demand on pump power variation, GE Renewable Energy develops since 10 years variable speed machines (also called Doubly Fed Induction Generators or DFIG). Within turbogenerators, the phenomenon of circulating currents in Roebe ...

EPFL2019

Prefrontal-Premotor Pathways and Motor Output in Well-Recovered Stroke Patients

Friedhelm Christoph Hummel

Structural brain imaging has continuously furthered our knowledge how different pathways of the human motor system contribute to residual motor output in stroke patients. Tract-related microstructure of pathways between primary and premotor areas has been ...

2019

MEMS Generator Study for an Embedded Energy Harvesting System

Jasha Poliakine

This work has been triggered by an industrial project targeting the development of a novel regulation system for a mechanical watch. Mechanical watches have been known for over a century as one of the finest example of energy autonomous devices, embodying ...

EPFL2018

Synergistic but independent: The role of corticospinal and alternate motor fibers for residual motor output after stroke

Friedhelm Christoph Hummel

Background Brain imaging has shown that not only the cortico-spinal tract (CST), but also alternate corticofugal motor fibers (aMF), such as the cortico-rubro-spinal and cortico-reticulo-spinal tract, influence residual motor output after stroke. So far, s ...

2017

Controlling the Electrical State via Uncertain Power Injections in Three-Phase Distribution Networks

Jean-Yves Le Boudec, Mario Paolone, Cong Wang

We consider the problem of controlling the electrical state of a three-phase distribution network by enforcing the explicit power injection. More precisely, we assume that the power injection is constrained to reside in some uncertainty set, and the proble ...

2017

Potential of Flex-PCB Winding in Coreless Tubular Permanent Magnet Synchronous Machines

Yves Perriard, Bruno Dehez, François Baudart

Many applications are limited by the performance of the motors that power them. In the small power range, slotless BLDC motors are commonly used due to their intrinsic high power density and smooth torque characteristic. However, recent work has shown that ...

2016