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Rikken G.L.J.A.,CNRS French National High Magnetic Field Laboratory | Van Tiggelen B.A.,CNRS Physics and Models in Condensed Media Laboratory
Physical Review Letters

The Abraham force exerted by a time-dependent electromagnetic field on neutral, polarizable matter has two contributions. The one induced by a time-varying magnetic field and a static electric field is reported here for the first time. We discuss our results in the context of the radiative momentum in matter. Our observations are consistent with Abraham's and Nelson's versions for radiative momentum. © 2012 American Physical Society. Source

Rikken G.L.J.A.,CNRS French National High Magnetic Field Laboratory | Van Tiggelen B.A.,CNRS Physics and Models in Condensed Media Laboratory
Physical Review Letters

We report the observation by a new method of mechanical momentum transferred to gas phase atoms and molecules upon application of crossed oscillating electric and static magnetic fields. We identify this momentum as the microscopic analogue of the classical Abraham force. Two QED predictions of additional magnetoelectrically induced mechanical momentum are addressed. One of them is experimentally refuted; the other is found to be currently below our experimental detection. © 2011 American Physical Society. Source

Battesti R.,CNRS French National High Magnetic Field Laboratory
Reports on progress in physics. Physical Society (Great Britain)

In this report we show that a vacuum is a nonlinear optical medium and discuss what the optical phenomena are that should exist in the framework of the standard model of particle physics. We pay special attention to the low energy limit. The predicted effects for photons of energy smaller than the electron rest mass are of such a level that none have yet been observed experimentally. Progress in field sources and related techniques seem to indicate that in a few years vacuum nonlinear optics will be accessible to human investigation. Source

Brooks J.S.,CNRS French National High Magnetic Field Laboratory
Chemical Society Reviews

The purpose of this critical review is twofold: first, to review organic "small molecule" crystalline materials in terms of structure and function; and second, to consider if and how such materials might eventually enter the realm of device applicability. This area, one of the most interdisciplinary fields of research in contemporary materials science, embraces chemistry, physics, engineering, biology, theory and computation. The review therefore attempts to treat a relatively large number of examples including fundamental physical and electronic structure, single component and charge transfer complexes, physical properties of single crystalline materials, thin film and single crystal electronic and photonic devices, functional materials, and bio-inspired structures. The point of view is that of an experimental physicist, and in this context, challenges and possible routes to further advances in the development and utilization of organic small molecule materials are discussed for both fundamental and applied purposes (153 references). © 2010 The Royal Society of Chemistry. Source

Performance degradation of Nb3Sn cable-in-conduit conductors (CICCs) is a critical issue in large-scale magnet design such as the International Thermonuclear Experimental Reactor (ITER) and the series-connected hybrid (SCH) magnets currently under development at the National High Magnetic Field Laboratory (NHMFL). Not only the critical current is significantly lower than expectations but also the voltage-current characteristic is observed to have a much broader transition from a single strand to a CICC cable. The variation of conductor voltage-current characteristic as a result of cable electromagnetic, mechanical and thermal interactions is challenging to model. In this paper, we use a new numerical model, called the Florida electro-mechanical cable model (FEMCAM) benchmarked against 40 different conductor tests, to study the influence of bending strain and current non-uniformity on the critical current and n-value of Nb3Sn strands and CICC cables. The new model combines thermal bending effects during cool-down, electromagnetic bending effects during magnet operation and current transfer in strands with filament fracture. The n-value of a strand under bending is derived from integration of filament critical current over strand cross-section for full and no current transfer. The cable n-value is obtained from the power law relation of cable electric field and critical current curve. By comparing numerical results with measurements of advanced Nb3Sn strands and various CICC cables, we demonstrate that FEMCAM is self-consistent in modeling inter-filament current transfer. The new model predicts that Ic degradation of bent strands initially follows closely full current transfer but starts deviating and falls between full and no current transfer with an increasing bending strain. The results agree with recent TARSIS measurements for less than 1% bending strain mostly interested in practice. The strand n-value degradation from FEMCAM with no filament current transfer agrees better with measurements than that from full current transfer. Finally, FEMCAM simulated cable n-values are compared with various CICC measurements. The results imply that FEMCAM is a useful tool for the design of Nb3Sn-based CICCs and both thermal bending and electromagnetic bending play important roles in CICC performance. © 2009 Elsevier Ltd. All rights reserved. Source

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