Plane-wave propagation in media with electromagnetic anisotropy

2021 ◽  
Author(s):  
David Romero-Abad ◽  
Jose Pedro Reyes Portales ◽  
Roberto Suárez-Córdova
Keyword(s):  
Plane Wave ◽  
Electromagnetic Waves ◽  
Wave Equations ◽  
Refraction Index ◽  
Pedagogical Approach ◽  
Undergraduate Level ◽  
Quartic Equation ◽  
Principal Axes ◽  
The Subject ◽  
Magnetic Tensors

Abstract The propagation of electromagnetic waves in a medium with electrical and magnetic anisotropy is a subject that is not usually handled in conventional optics and electromagnetism books. During this work, we try to give a pedagogical approach to the subject, using tools that are accessible to an average physics student. In this article, we obtain the Fresnel relation in a media with electromagnetic anisotropy, which corresponds to a quartic equation in the refraction index, assuming only that the principal axes of the electric and magnetic tensors coincide. Additionally, we find the geometric location related to the different situations the discriminant of the quartic equation provides. In order to illustrate our findings, we determine the refractive index together with the plane wave equations for certain values of the parameters that meet the established conditions. The target readers of the paper are students pursuing physics at the intermediate undergraduate level.

Book Review: Writing for Academic Journals Second Edition

2021 ◽  
Author(s):  
Andi Asrifan ◽  
Abd Ghofur
Keyword(s):  
Health Service ◽  
Professional Life ◽  
Professional Lives ◽  
Academic Journals ◽  
Writing For Publication ◽  
Undergraduate Level ◽  
Publish Or Perish ◽  
The Subject ◽  
The Many

Anyone who wants to get ahead in academic or professional life today knows that it’s a question of publish or perish. This applies to colleges, universities, and even hospital Trusts. Yet writing for publication is one of the many skills which isn’t formally taught. Once beyond undergraduate level, it’s normally assumed that you will pick up the necessary skills as you go along.Writing for Academic Journalsseeks to rectify this omission. Rowena Murray is an experienced writer on the subject (author of How to Write a Thesis and How to Survive Your Viva) and she is well aware of the time pressures people are under in their professional lives. What she has to say should be encouraging for those people in ‘new’ universities, people working in disciplines which have only recently been considered academic, and those in professions such as the health service which are under pressure to become more academic.

Electromagnetic waves

2018 ◽  
Author(s):  
Nathalie Deruelle ◽  
Jean-Philippe Uzan
Keyword(s):  
Plane Wave ◽  
Electromagnetic Waves ◽  
Maxwell Equations ◽  
Plane Waves ◽  
Geometrical Optics ◽  
Particle Detection ◽  
Spatial Coordinates ◽  
A Charge

This chapter examines solutions to the Maxwell equations in a vacuum: monochromatic plane waves and their polarizations, plane waves, and the motion of a charge in the field of a wave (which is the principle upon which particle detection is based). A plane wave is a solution of the vacuum Maxwell equations which depends on only one of the Cartesian spatial coordinates. The monochromatic plane waves form a basis (in the sense of distributions, because they are not square-integrable) in which any solution of the vacuum Maxwell equations can be expanded. The chapter concludes by giving the conditions for the geometrical optics limit. It also establishes the connection between electromagnetic waves and the kinematic description of light discussed in Book 1.

SOME UNPOLARIZED GOWDY COSMOLOGIES AND NONCOLINEAR COLLIDING PLANE WAVE SPACETIMES

1998 ◽  
Vol 07 (02) ◽  
pp. 237-247 ◽  
Author(s):  
J. B. GRIFFITHS ◽  
G. A. ALEKSEEV
Keyword(s):  
Plane Wave ◽  
Electromagnetic Waves ◽  
Linear Equations ◽  
Ernst Equation ◽  
Complex Solutions

A method for obtaining a class of complex solutions of the Ernst equation is described which is based on a set of linear equations. This method is applied to generate families of unpolarized vacuum and electrovac G2 cosmologies and nondiagonal solutions describing colliding plane gravitational and gravito-electromagnetic waves.

Integrating Constructionism and Instructionism in Educational Hypermedia Programs

1997 ◽  
Vol 17 (3) ◽  
pp. 231-247 ◽  
Author(s):  
Amnon Shabo
Keyword(s):  
Subject Matter ◽  
Linear Structure ◽  
Learning Objectives ◽  
Pedagogical Approach ◽  
Original Meaning ◽  
Learning Path ◽  
Non Linear ◽  
The Subject ◽  
Linear Instruction ◽  
Educational Hypermedia

In many educational hypermedia programs, the original meaning of hypertext influenced the entire pedagogical approach underlying the programs. This meant that learners were free to navigate, construct, and choose their learning path. In addition, no learning objectives were mandatory, and the processes of hypertext navigation and artifact constructions were emphasized. The problem of this trend was that learners received little feedback to guide them on how to use the non-linear structure, and not all could acquire important skills and knowledge of the subject matter. This article deals with an attempt to integrate linear instruction elements into hypermedia programs in order for learners to benefit from the advantages of both approaches. It offers feedback as a connecting unit in such an integration and suggests a model of feedback that fades in and out, based on the fading-out model of scaffolding traditionally used in the apprenticeship approach. A few projects are described to illustrate these ideas.

Using round table labs to complement didactic lectures and experimental labs.

1998 ◽  
Vol 274 (6) ◽  
pp. S68 ◽  
Author(s):  
N P Nekvasil
Keyword(s):  
Round Table ◽  
Analytic Thinking ◽  
Physiological Mechanisms ◽  
Traditional Lecture ◽  
Undergraduate Level ◽  
Hands On ◽  
Hands On Learning ◽  
The Subject ◽  
Didactic Lecture ◽  
Physiology Students

In an effort to teach the volume of material needed by physiology students as well as to enhance the student's understanding of physiological mechanisms, a combination of teaching methods is being used at the undergraduate level. Didactic lectures are used to convey the mass of information needed, experimental labs are used to aid the student in visualizing concepts, and situational labs [called round table labs (RTLs) here] are used to provide an opportunity for the student to learn, in a risk-free setting, how to answer application questions. The RTLs utilize discussion, writing, verbal communication, and analytic thinking. The major emphasis of the RTLs is on the integrative nature of physiology. Use of the RTLs bridges, the gap among the facts learned in the didactic lecture, the hands-on learning of the experimental lab, and the need to be able to apply what is being learned. Using this combination facilitates student learning such that the student reaches a level of proficiency with the subject beyond that which can be attained with the more traditional lecture-exam format.

PHOTONIC GAPS IN PERIODIC DIELECTRIC STRUCTURES

1992 ◽  
Vol 06 (03) ◽  
pp. 139-144 ◽  
Author(s):  
C.T. CHAN ◽  
K.M. HO ◽  
C.M. SOUKOULIS
Keyword(s):  
Plane Wave ◽  
Electromagnetic Waves ◽  
Expansion Method ◽  
Dielectric Materials ◽  
Band Gaps ◽  
Plane Wave Expansion ◽  
Photonic Band Gaps ◽  
Plane Wave Expansion Method ◽  
Dielectric Structures ◽  
Photonic Band

Using a plane wave expansion method, we solved the Maxwell’s equations for the propagation of electromagnetic waves inside periodic dielectric materials, and found the existence of photonic band gaps in several classes of periodic dielectric structures.

The Wavefield Radiated Into an Elastic Half-Space by a Transducer of Large Aperture

1988 ◽  
Vol 55 (2) ◽  
pp. 398-404 ◽  
Author(s):  
John G. Harris
Keyword(s):  
Power Series ◽  
Plane Wave ◽  
Half Space ◽  
Wave Equations ◽  
Ultrasonic Transducer ◽  
Elastic Half Space ◽  
The Other ◽  
Circular Region ◽  
Asymptotic Power ◽  
Normal Traction

The wavefield radiated into an elastic half-space by an ultrasonic transducer, as well as the radiation admittance of the transducer coupled to the half-space, are studied. Two models for the transducer are used. In one an axisymmetric, Gaussian distribution of normal traction is imposed upon the surface, while in the other a uniform distribution of normal traction is imposed upon a circular region of the surface, leaving the remainder free of traction. To calculate the wavefield, each wave emitted by the transducer is expressed as a plane wave multiplied by an asymptotic power series in inverse powers of the aperture’s (scaled) radius. This reduces the wave equations satisfied by the compressional and shear potentials to their parabolic approximations. The approximations to the radiated waves are accurate at a depth where the wavefield remains well collimated.

scholarly journals Recent Research in English Urban History, c. 1450-1650

2013 ◽  
Vol 11 (2) ◽  
pp. 31-39
Author(s):  
Robert Tittler
Keyword(s):  
Case Studies ◽  
Urban Setting ◽  
Quantitative Methodology ◽  
English History ◽  
Constitutional Development ◽  
Undergraduate Level ◽  
Industrial Town ◽  
The Subject ◽  
University Course ◽  
Short Time

Interest in few areas of English history has developed as fast in the last decade as in the pre-industrial urban setting. Where there were few serious academics at work and little instruction at the undergraduate level, we now have an entire — and very impressive — Open University course on the field, and the genre of urban case studies seems to have replaced the shire as favoured ground for English doctoral theses in history. Much of the recent work on pre-industrial urban problems continues to probe questions raised a decade or more ago. These studies, which deal with political factionalism, constitutional development, town-crown relations and similar problems, must not be dismissed as obsolete; the enormous diversity of the subject itself necessitates a great number of case studies before generalizations may be obtained. Equally important and perhaps more innovative in method are those studies of fresher conceptualization, typically more interdisciplinary in approach and more inclined towards quantitative methodology. These rely heavily on the work of the anthropologist, the demographer and geographer and have in a short time greatly expanded the bounds of the historian of the pre-industrial town and city.

Twins of Marcasite in Regular Disposition Upon Cubes of Pyrites

1891 ◽  
Vol 9 (43) ◽  
pp. 209-210 ◽  
Author(s):  
C. O. Trechmann
Keyword(s):  
Principal Axis ◽  
Vertical Axis ◽  
Principal Axes ◽  
The Subject ◽  
Diagonal Axis ◽  
Lateral Axis

The subject of this note derives interest less from its novelty than from the beautiful manner in which the intergrowth is exemplified in Nature. As Sadebeek has shown, the intergrowth of marcasite and pyrites takes place according to two laws.(1) The vertical axis of marcasite is parallel with a principal axis of pyrites; one of the two other principal axes of the latter being parallel with the combination edge m (110) ∞P : c (001) 0P of the former ; or, in other words, the vertical and one lateral axis (ab) of marcasite coincide with two principal axes of pyrites.(2) The vertical axis of marcasite is parallel with a principal axis of pyrites; the braehydiagonal axis is parallel with a diagonal axis of pyrites.

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