Physics 318 — Fundamentals of Electromagnetism

Objectives and Goals

Overview:
This is the first course in a two-semester sequence covering classical electromagnetic theory at the graduate level. The major topics for PHY 318 include electrostatics, magnetostatics, electromagnetic induction, conservation laws, an introduction to covariant electrodynamics, and electromagnetic waves. The main purpose is teach students the language and major concepts of electromagnetic theory in forms that are useful for physics research as well as advanced coursework in condensed matter physics, quantum field theory, optical physics, and nuclear physics. The course may also be useful to graduate students in other departments, for example, chemistry and electrical engineering. PHY 318 includes a substantial review electromagnetism at the intermediate undergraduate level, through the assignment of several intermediate level problems for homework.
Related courses and prerequisites:
The two courses most closely tied to PHY 318 are PHY 230 - a prerequisite covering mathematical methods, and PHY 319 - the second semester of the graduate electromagnetism sequence. The PHY 230 material that is most useful for PHY 318 includes ordinary differential equations, Sturm-Liouville theory, techniques of complex variables (especially contour integration), asymptotic expansions, and familiarity with Mathematica. The continuation course PHY 319 focuses on the following topics: an in-depth treatment of covariant electrodynamics, radiation theory, waveguides, vector and scalar diffraction theory, and special topics. A minimal prerequisite for PHY 318/319 includes a good general physics course in electricity and magnetism and knowledge of mathematical techniques at the level of PHY 230; also, it is strongly recommended that students should have taken at least one semester of an intermediate undergraduate electromagnetism course at the level of Griffiths.
Objectives:
To present the fundamental topics of classical electromagnetic (EM) theory. A minimal set of topics includes: electrostatics (including boundary value problems, variational methods, method of images, Green function methods, multipole expansion, Maxwell stress tensor, dielectric materials); magnetostatics; magnetic materials; induction phenomena; Maxwell's equations; gauge transformations; conservation theorems; EM field tensor; transformation of E and B fields under Lorentz transformation; EM waves in free space; scattering of EM waves from planar dielectric interfaces; the Fresnel equations; introduction to the general theory of frequency-dependent dielectric functions. Much of the electrostatics discussion centers around the development and use of mathematical techniques for solving boundary value problems. The lectures are generally at the level of Jackson, while the assigned homework consists of a roughly equal mix of Jackson-level and Griffiths-level problems.

Methods and Approach

Lectures:
PHY 318 is currently taught through 75-minute lectures (2 per week) in which the instructor makes a chalkboard presentation. Student are encouraged to ask questions.
Homework:
There are five required homework sets per semester. (There is also one optional problem set at the very beginning of the semester that reviews useful techniques of vector calculus.) Each homework set consists of 10 - 12 problems, about half of which are at the intermediate level - typically assigned from Griffiths' text, while the remainder come from Jackson's text or are developed by the instructor. The final problem set typically includes 3 or 4 challenging problems that tie together multiple concepts of the course. Students are encouraged to discuss homework problems with their peers, the instructor, and the TA. However, it is very important that students write up their solutions independently.
Texts:
Currently, the two required texts are:
  • J. D. Jackson, Classical Electrodynamics, 3rd ed.
  • D. J. Griffiths, Introduction to Electrodynamics, 3rd ed.
Although the discussion in Jackson tends to be rather formal and intricate, it remains the canonical graduate textbook for classical electromagnetism. The problems are generally challenging and a number of them help students develop both their physical insight as well as their mathematical abilities. Griffiths is an excellent intermediate-level undergraduate text. With the possible exception of covariant electrodynamics, the discussion is highly readable and provides a good prelude to related material in Jackson. Other texts that have been found to be useful for lecture material and ideas for homework problems include:
  • Landau and Lifshitz, vol. 2, The Classical Theory of Fields
  • Landau and Lifshitz, vol. 8, Electrodynamics of Continuous Media
  • Francis E. Low, Classical Field Theory
  • Sandra C. Chapman, Core Electrodynamics
Exams and Grading:
There are two in-class 90 minute exams for this course. These are closed book and closed notes exams, and consist of five short answer questions and two problems. Exams are designed to test students' factual knowledge of the material, ability to formulate and solve problems, and ability to make order-of-magnitude estimates. The first exam covers all of the electrostatics material and is typically given in the seventh week of the semester. The second exam covers all of the course material up to electromagnetic waves and is typically given in the 13th week of the semester, approximately two weeks prior to the last lecture of the course. The format and difficulty of both exams is similar to the electromagnetism part of the qualifying exam. In fact, one reason for giving the second exam before semester's end is to ensure that students receive effective feedback on their exam performance. Grades are determined by the homework (40%), Exam #1 (20 %), and Exam #2 (40%).

Sample Syllabus

  • 318 sample lecturing schedule (assumes 75 minutes per lecture).
  • L1 - Electrostatics: Coulomb's Law, electric field
  • L2 - Electrostatics: Gauss Law, potential, Laplace and Poisson Equations
  • L3 - Electrostatics: conductors, uniqueness of solutions, Green functions
  • L4 - Electrostatics: electrostatic energy, capacitance, variational principles
  • L5 - Electrostatics: method of images
  • L6 - Electrostatics: separation of variables - Cartesian case
  • L7 - Electrostatics: separation of variables - spherical case
  • L8 - Electrostatics: multipole expansion
  • L9 - Electrostatics: separation of variables - cylindrical case
  • L10 - Electrostatics: Green functions - spectral representation, Cartesian example
  • L11 - Electrostatics: Green functions - cylindrical example; potential near edges
  • L12 - Electrostatics: dielectrics 1
  • L13 - Electrostatics: dielectrics 2 (including Clausius-Mossotti relation)
  • L15 - Relativity: Lorentz transformation, covariant and contravariant 4-vectors
  • L16 - Relativity: charge invariance, 4-potential, electromagnetic field tensor
  • L17 - Relativity: Lorentz force law, Lorentz transformation properties of E and B fields, Maxwell

  • Equations in covariant form

  • L18 - Magnetostatics: Biot-Savart and Ampere Laws
  • L19 - Magnetostatics: magnetic dipoles; magnetic materials; para-, dia-, and ferro-magnetism.
  • L20 - Magnetic energy, inductance, and Faraday's Law
  • L21 - Examples of induction; eddy currents
  • L22 - Maxwell's equations, boundary conditions, gauge transformations
  • L23 - conservation laws (charge, energy, momentum, angular momentum); Poynting vector,

  • Maxwell stress tensor

  • L24 - electromagnetic waves: plane waves in homogeneous media
  • L25 - electromagnetic waves: normal and oblique scattering from a dielectric interface; Fresnel Eqs.
  • L26 -electromagnetic waves: Sellmeier and Drude models for dispersion, dielectric relaxation, plasma frequency
  • L27 - electromagnetic waves: reflectivity of a metal (Hagen-Rubens relation), general properties of dielectric functions (Kramers-Kronig relations)
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