Nonlinear surface polaritons in 2D electron system in high magnetic field

The paper deals with the theoretical investigation of nonlinear surface polaritons (NSP) in isolated two-dimensional electron system (2DES) arranged at the interface between linear and nonlinear media and placed into the external quantizing magnetic field directed perpendicularly to 2DES. We consider that nonlinear medium dielectric permeability depends upon the tangential component of electric field only. It is shown that under the integer quantum Hall effect conditions all NSP characteristics are represented by the quantized values. It is found that the NSP spectrum contains two NSP modes - high-frequency and low-frequency ones. It is shown that the NSP can exist only in the case where the value of tangential component of electric field at the interface is less than a certain critical value. It is found that the resonant interaction between the NSP high-frequency mode and surface polariton mode occurs in the vicinity of the cyclotron resonance subharmonic. Received 23 September 2001 / Received in final form 31 January 2002 Published online 2 October 2002 RID="a" ID="a"e-mail: bludov@ire.kharkov.ua     

Nonlinear cyclotron resonant wave-particle interaction in a nonuniform magnetic field

Quasilinear analysis of wave-particle interactions is presented for plasma flowing in a weakly nonuniform magnetic field configuration. The method presented is based on a scale separation between the length scales of quasilinear relaxation and the magnetic field inhomogeneity, allowing one to obtain large scale solutions for both particle distribution functions and wave spectra, without going into the details of the small scale quasilinear relaxation. The numerical example shows the existence of a secondary instability for an initially stable particle distribution function.     

Nonlinear s-polarized surface plasmon polaritons

We have examined the dispersion relations for s-polarized surface plasmon polaritons, guided by (a) the interface between a semi-infinite metal and dielectric medium, and (b) a metal film bounded by semi-infinite dielectric media for situations in which one or more of the dielectric media are characterized by an intensity-dependent refractive index. We found that s-polarized waves satisfy the dispersion relations for very thin metal films bounded by nonlinear dielectric media. These waves exist only for power levels above a threshold that depends on the material parameters. We also comment on the experimental feasibility of observing these waves.     

Magnetorotational instability in a nonuniform magnetic field

It is shown that the characteristics of the magnetorotational instability noticeably change in the presence of the inhomogeneity of a magnetic field in which rotation occurs. A decrease in the magnetic field with an increase in the distance from the rotation center, which is typical for astrophysical objects, can lead to a significant decrease in the threshold velocity of the object medium rotation, as well as to mitigation of the requirements on a rotation velocity profile that are necessary for the development of instability. Other examples that demonstrate the indicated effects are given.     

Magnetorotational instability in a nonuniform magnetic field

It is shown that the characteristics of the magnetorotational instability noticeably change in the presence of the inhomogeneity of a magnetic field in which rotation occurs. A decrease in the magnetic field with an increase in the distance from the rotation center, which is typical for astrophysical objects, can lead to a significant decrease in the threshold velocity of the object medium rotation, as well as to mitigation of the requirements on a rotation velocity profile that are necessary for the development of instability. Other examples that demonstrate the indicated effects are given. Original Russian Text ? V.I. Ilgisonis, I.V. Khalzov, 2007, published in Pis’ma v Zhurnal éksperimental’noĭ i Teoreticheskoĭ Fiziki, 2007, Vol. 86, No. 11, pp. 815–818.     

Azimuthal surface waves at the plasma-metal boundary in a nonuniform toroidal magnetic field

The propagation of electromagnetic surface waves with extraordinary polarization across the circular axis of a metal ring in a magnetized plasma is studied using perturbation theory. The amplitude of the fundamental mode of these waves is determined to within second-order terms, and the amplitudes of the nearest satellite modes are found correct to first-order terms. The correction to the eigenfrequency that comes from the nonuniformity of a constant toroidal magnetic field is shown be a second-order quantity.     

Self-localized nonlinear surface magnetic polaritons in a ferromagnetic medium

The properties of electromagnetic waves propagating in a semibounded, nonlinear, ferromagnetic medium are investigated. It is shown that under certain conditions the interaction between the spin and electromagnetic waves results in the localization of volume polaritons near the surface. Self-localization of surface polaritons due to the nonlinear properties of the medium occurs thereby. The nonlinear Schrödinger equation for nonlinear surface and volume polaritons is derived, and the conditions under which solitons of these waves exist are determined. The wave intensity required to observe the predicted effects is estimated.     

Exciton polaritons in quantum wells in a transverse magnetic field

Physics of the Solid State - This paper reports on a study of the exciton polariton region in reflection spectra of wide CdTe/CdZnTe quantum wells (with well width exceeding by far the exciton Bohr...     

Nonlinear resonance-enhanced excitation of surface plasmon polaritons

We theoretically investigate nonlinear resonance-enhanced excitation of surface plasmon polaritons in a metal coated by a one-dimensional photonic crystal. Tunneling modes above the air-light line can be directly excited in this structure. Then, with suitable parameters, photon energy and momentum conservation between the tunneling mode and the surface plasmon polaritons can be realized by means of nonlinear four-wave mixing. Compared with the nonlinear excitation of surface plasmon polaritons in a bulk metal [Phys. Rev. Lett. 103, 266802 (2009)], the conversion efficiency in our structure is noticeably enhanced.     

Efficiency enhancement in gyroklystrons with a nonuniform static magnetic field

The main equations needed to calculate the efficiency of a gyroklystron in the one-velocity approximation and in the presence of a spread in electron velocities are given. The influence of the longitudinal structure of the static magnetic field on the efficiency of a two-cavity gyroklystron is investigated. The characteristics of a physical model of a gyroklystron for the 3-cm wavelength range are given for different longitudinal magnetic field distributions in the interaction space. The calculated and experimental data are in good agreement.Institute of Applied Physics, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, No. 10, pp. 1321–1334, October, 1994.     

Recuperation in superpower Cherenkov generators with a nonuniform magnetic field

We consider an effective method for increasing the total efficiency of relativistic Cherenkov generators, viz., recuperation. It has been found that, for a generator with an efficiency smaller than 15%, recuperation makes it possible to obtain an increase in the efficiency that exceeds 50% (from 12% to 68%). In generators with initially high efficiency (more than 50%), recuperation may turn out to be ineffective.     

Nonlinear electrodynamics in a superstrong magnetic field

Using a Feynman technique in a two-dimensional space we have calculated an electron propagator and a photon polarization tensor in a superstrong magnetic field $\text{B ? B}{}_{\mathrm{<mtext>0</mtext>}}\text{=}\text{m}{}^{\mathrm{<mtext>2</mtext>}}\text{e}\text{=}\text{4.41 × 10}{}^{13}$ G. Some applications are briefly discussed.     

Effect of dissipation on the properties of surface polaritons in GaAs/AlGaAs heterojunctions in a quantizing magnetic field

A study is reported of nonradiative surface and bulk polaritons in GaAs/Al_xGa_1−x As real heterojunctions under conditions favoring integer-quantum Hall effect (IQHE) and in the presence of dissipation in a two-dimensional electron layer. The conditions of their existence, the spectrum, and damping have been determined. It is shown that under IQHE conditions all aspects of surface and bulk polaritons are quantized. It is found that, as the wave number is varied, surface and bulk polaritons can transform continuously into one another. The possibilities of experimental observation of nonradiative polaritons are discussed. Fiz. Tverd. Tela (St. Petersburg) 41, 705–711 (April 1999)     

Polarized nonequilibrium Bose-Einstein condensates of spinor exciton polaritons in a magnetic field

The effect of a magnetic field on a spinor exciton-polariton condensate has been investigated. A quenching of a polariton Zeeman splitting and an elliptical polarization of the condensate have been observed at low magnetic fields B<2 T. The effects are attributed to a competition between the magnetic field induced circular polarization buildup and the spin-anisotropic polariton-polariton interaction which favors a linear polarization. The sign of the circular polarization of the condensate emission at B<3 T is negative, suggesting that a dynamic condensation in the excited spin state rather than the ground spin state takes place in this magnetic field range. From about 2T on, the Zeeman splitting opens and from then on the slope of the circular polarization degree changes its sign. For magnetic fields larger than the 3 T, the upper spin state occupation is energetically suppressed and circularly polarized condensation takes place in the ground state.