Calculus of moving surfaces and singular wave-fronts in ideal magnetohydrodynamics

2016 ◽  
Author(s):  
Michael Grinfeld ◽  
Pavel Grinfeld
Keyword(s):  
Wave Fronts ◽  
Ideal Magnetohydrodynamics ◽  
Singular Wave ◽  
Calculus Of Moving Surfaces

scholarly journals LANDAU EQUATIONS AND ASYMPTOTIC OPERATION

1999 ◽  
Vol 14 (05) ◽  
pp. 683-715 ◽  
Author(s):  
F. V. TKACHOV
Keyword(s):  
Minkowski Space ◽  
Feynman Diagrams ◽  
Simple Derivation ◽  
Wave Fronts ◽  
Theoretic Technique ◽  
Singular Wave

The pinched/nonpinched classification of intersections of causal singularities of propagators in Minkowski space is reconsidered in the context of the theory of asymptotic operation as a first step towards extension of the latter to non-Euclidean asymptotic regimes. A highly visual distribution-theoretic technique of singular wave fronts is tailored to the needs of the theory of Feynman diagrams. Besides a simple derivation of the usual Landau equations in the case of the conventional singularities, the technique naturally extends to other types of singularities, for example due to linear denominators in non-covariant gauges, etc. As another application, the results of Euclidean asymptotic operation are extended to a class of quasi-Euclidean asymptotic regimes in Minkowski space.

scholarly journals Controlling wave fronts with tunable disordered non-Hermitian multilayers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Denis V. Novitsky ◽  
Dmitry Lyakhov ◽  
Dominik Michels ◽  
Dmitrii Redka ◽  
Alexander A. Pavlov ◽  
...  
Keyword(s):  
Incident Light ◽  
Passage Time ◽  
Photonic Devices ◽  
Gain Saturation ◽  
Wave Fronts ◽  
Optical Effects ◽  
Front Shape ◽  
Optical Applications ◽  
Increasing Demand ◽  
First Time

AbstractUnique and flexible properties of non-Hermitian photonic systems attract ever-increasing attention via delivering a whole bunch of novel optical effects and allowing for efficient tuning light-matter interactions on nano- and microscales. Together with an increasing demand for the fast and spatially compact methods of light governing, this peculiar approach paves a broad avenue to novel optical applications. Here, unifying the approaches of disordered metamaterials and non-Hermitian photonics, we propose a conceptually new and simple architecture driven by disordered loss-gain multilayers and, therefore, providing a powerful tool to control both the passage time and the wave-front shape of incident light with different switching times. For the first time we show the possibility to switch on and off kink formation by changing the level of disorder in the case of adiabatically raising wave fronts. At the same time, we deliver flexible tuning of the output intensity by using the nonlinear effect of loss and gain saturation. Since the disorder strength in our system can be conveniently controlled with the power of the external pump, our approach can be considered as a basis for different active photonic devices.

High-order harmonic wave fronts generated with controlled astigmatic infrared laser

2008 ◽  
Vol 25 (7) ◽  
pp. B161 ◽  
Author(s):  
Constance Valentin ◽  
Julien Gautier ◽  
Jean-Philippe Goddet ◽  
Christoph Hauri ◽  
Tatiana Marchenko ◽  
...  
Keyword(s):  
Harmonic Wave ◽  
Infrared Laser ◽  
High Order ◽  
Wave Fronts ◽  
High Order Harmonic

scholarly journals Wave Fronts in a Causality-Violating Gödel-Type Metric

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Thomas P. Kling ◽  
Faizuddin Ahmed ◽  
Megan Lalumiere
Keyword(s):  
Wave Front ◽  
Space Time ◽  
Wave Fronts ◽  
Light Rays ◽  
Synchronized Clocks

The light rays and wave fronts in a linear class of the Gödel-type metric are examined to reveal the causality-violating features of the space-time. Noncausal features demonstrated by the development of unusual wave front singularities are shown to be related to the nonmonotonic advance of time along the light rays, as measured by a system of observers at rest with respect to one another with synchronized clocks.

The accumulation continua in ideal magnetohydrodynamics

2003 ◽  
Vol 10 (2) ◽  
pp. 413-418 ◽  
Author(s):  
G. O. Spies ◽  
J. A. Tataronis
Keyword(s):  
Ideal Magnetohydrodynamics
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