Propagation of electromagnetic waves in a regular waveguide with multiperiodically modulated media

The propagation of electromagnetic waves in an ideal regular waveguide, filling of which is periodically modulated in space and time, is considered. It is assumed that the modulation depths are small and the modulation of the waveguide filling does not lead to the interaction between different waveguide modes. Wave equations are obtained for transverse-electric (TE) and transverse-magnetic (TM) fields in the waveguide with respect to the longitudinal components of the magnetic and electric vectors, respectively, are obtained. They represent second order partial differential equations with periodic coefficients. By changing the variables these equations are reduced to ordinary differential equations with periodic coefficients of the Mathieu-Hill type. Solutions of these equations are found in the first approximation with respect to small modulation depths in the region of “weak” interaction between the signal wave and the modulation wave (the Wulff-Bragg condition is not satisfied). The obtained results show that TE and TM fields in the waveguide in the above approximation are represented as the sum of three space-time harmonics (zero and plus and minus first) with complicated amplitudes and frequencies.

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To the theory of induced scattering of electromagnetic waves by an electron beam in a regular waveguide

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment ◽

10.1016/0168-9002(91)90930-o ◽

1991 ◽

Vol 304 (1-3) ◽

pp. 559-563 ◽

Cited By ~ 4

Author(s):

N.I. Karbushev ◽

A.D. Shatkus

Keyword(s):

Electron Beam ◽

Electromagnetic Waves ◽

Regular Waveguide

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Seti Space Missions

International Astronomical Union Colloquium ◽

10.1017/s0252921100015372 ◽

1997 ◽

Vol 161 ◽

pp. 761-776 ◽

Cited By ~ 1

Author(s):

Claudio Maccone

Keyword(s):

Electromagnetic Waves ◽

Space Missions ◽

Gravitational Lens ◽

The Sun ◽

Space Antenna ◽

Focal Distance ◽

Large Space ◽

The Earth ◽

Space Antennas ◽

New Space

AbstractSETI from space is currently envisaged in three ways: i) by large space antennas orbiting the Earth that could be used for both VLBI and SETI (VSOP and RadioAstron missions), ii) by a radiotelescope inside the Saha far side Moon crater and an Earth-link antenna on the Mare Smythii near side plain. Such SETIMOON mission would require no astronaut work since a Tether, deployed in Moon orbit until the two antennas landed softly, would also be the cable connecting them. Alternatively, a data relay satellite orbiting the Earth-Moon Lagrangian pointL2would avoid the Earthlink antenna, iii) by a large space antenna put at the foci of the Sun gravitational lens: 1) for electromagnetic waves, the minimal focal distance is 550 Astronomical Units (AU) or 14 times beyond Pluto. One could use the huge radio magnifications of sources aligned to the Sun and spacecraft; 2) for gravitational waves and neutrinos, the focus lies between 22.45 and 29.59 AU (Uranus and Neptune orbits), with a flight time of less than 30 years. Two new space missions, of SETI interest if ET’s use neutrinos for communications, are proposed.

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Microwaves: Application in Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100158248 ◽

1990 ◽

Vol 48 (3) ◽

pp. 140-141

Author(s):

Anthony S-Y Leong ◽

David W Gove

Keyword(s):

Electron Microscopy ◽

Light Microscopy ◽

Chemical Reactions ◽

Electromagnetic Waves ◽

Tissue Fixation ◽

Primary Method ◽

Dipolar Molecules ◽

Wide Range ◽

Time Required ◽

Cryostat Sections

Microwaves (MW) are electromagnetic waves which are commonly generated at a frequency of 2.45 GHz. When dipolar molecules such as water, the polar side chains of proteins and other molecules with an uneven distribution of electrical charge are exposed to such non-ionizing radiation, they oscillate through 180° at a rate of 2,450 million cycles/s. This rapid kinetic movement results in accelerated chemical reactions and produces instantaneous heat. MWs have recently been applied to a wide range of procedures for light microscopy. MWs generated by domestic ovens have been used as a primary method of tissue fixation, it has been applied to the various stages of tissue processing as well as to a wide variety of staining procedures. This use of MWs has not only resulted in drastic reductions in the time required for tissue fixation, processing and staining, but have also produced better cytologic images in cryostat sections, and more importantly, have resulted in better preservation of cellular antigens.

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