High-order harmonic emission is investigated by numerical solution of the weakly relativistic, two-dimensional Schrödinger equation for the case of ultraintense laser-driven tightly bound systems (for example, multiply charged ions such as O7+ exposed to laser fields of the order of 1018 W cm−2 at 248 nm). In contrast to their usual substantial decrease, the low-order harmonics having an energy...

Rotation matrices (or Wigner D functions) are the matrix representations of the rotation operators in the basis of spherical harmonics. They are the key entities in the generation of symmetry-adapted functions by means of projection operators. Although their expression in terms of ordinary (complex) spherical harmonics and Euler rotation angles is well known, an alternative representation using...

In dynamic atomic force microscopy, nanoscale properties are encoded in the higher harmonics. Nevertheless, when gentle interactions and minimal invasiveness are required, these harmonics are typically undetectable. Here, we propose to externally drive an arbitrary number of exact higher harmonics above the noise level. In this way, multiple contrast channels that are sensitive to compositional...

Jussi Karttunen Current Harmonic Compensation in Dual Three-Phase Permanent Magnet Synchronous Machines Lappeenranta 2017 80 pages Acta Universitatis Lappeenrantaensis 751 Diss. Lappeenranta University of Technology ISBN 978-952-335-097-7, ISBN 978-952-335-098-4 (PDF) ISSN-L 1456-4491, ISSN 1456-4491 Dual three-phase electric machines can bring significant benefits over conventional threephase ...

The harmonic currents generated by the modern power supply equipment cause power system heating and also add to user power bills. Personal computers are the major equipments which use the modern power supply ie switched mode power supply (SMPS).These SMPS draw non-sinusoidal currents from the supply which results in generation of harmonics. Power quality of the distribution network is been dist...

Two energy hybrid filter systems were considered which reduce level of higher mains current harmonics. An advantage of such system is low demanded active filter power because in complements only passive filter operation. The first considered system has inverter switched on in series with shunt passive filter. Through optimization of control parameters it is able to eliminate specific higher mai...

High harmonics driven by two-color counterrotating circularly polarized laser fields are a unique source of bright, circularly polarized, extreme ultraviolet, and soft x-ray beams, where the individual harmonics themselves are completely circularly polarized. Here, we demonstrate the ability to preferentially select either the right or left circularly polarized harmonics simply by adjusting the...

Ten-millijoule 35-femtosecond laser pulses interact with a cell of helium or neon that extends from a focusing lens to an exit foil near the laser focus. High harmonic orders in the range of 50 to 100 are investigated as a function of focal position relative to the exit foil. An aperture placed in front of the focusing lens increases the brightness of observed harmonics by more than an order of...

We prove the existence of bound guided modes for the Helmholtz equation on lossless penetrable periodic slabs. We handle both robust modes, for which no Bragg harmonics propagate away from slab, as well as nonrobust standing modes, which exist in the presence of propagating Bragg harmonics. The latter are made possible by symmetries of the slab structure, which prevent coupling of energy to the...

We study Sobolev type estimates for the approximation order resulting from using strictly positive definite kernels to do interpolation on the n-sphere. The interpolation knots are scattered. Our approach partly follows the general theory of Golomb and Weinberger and related estimates. These error estimates are then based on series expansions of smooth functions in terms of spherical harmonics....