MPhys Physics with Astrophysics

Electromagnetic Radiation

To develop an understanding of the production, scattering and transmission of electromagnetic waves.

On completion successful students will be able to:

1. Use Maxwell's equations to describe the propagation of electromagnetic waves in vacuum.
2. Explain in detail how accelerated charges produce electromagnetic radiation, particularly in antennas.
3. Show with calculations how waves are propagated in dielectrics, conductors and plasmas.
4. Describe and calculate the properties of waves undergoing reflection and refraction at boundaries, and the scattering of waves by free and bound electrons.
5. Explain the properties of electromagnetic fields when guided by transmission lines and waveguides and calculate numerically their important parameters.
6. Describe and calculate the properties of sources of electromagnetic radiation, including cyclotron radiation, synchrotron radiation, Bremsstrahlung and Cerenkov radiation.
    

1. The Electromagnetic Field (3 lectures)

Maxwell's equations for E, B, Charge conservation
Potentials in electromagnetism
Energy in the electromagnetic field
Poynting's Theorem
Electromagnetic plane waves
Polarisation. Radiation Pressure

2.  Sources of Radiation (3 lectures)

Potentials in electromagnetism (dynamic fields)
Retarded potentials
Radiation from accelerated charge - Larmor formula
Hertzian dipole radiation. Antennae.

3.  Radiation in matter (5 lectures)

Maxwell's equations in media
Plane waves in matter. Refractive index
Radiation in dielectrics - dispersion
Radiation in conductors and plasmas

4.  Reflection, Refraction & Scattering (4 lectures)

Boundary conditions
Normal and Oblique Incidence Reflection from dielectric
Fresnel's equations. Total internal reflection
Reflection from metallic surface
Scattering from free electrons - Thomson scattering
Scattering by atoms - Rayleigh scattering

5.  Guided Radiation (4 lectures)

Transmission lines. Characteristic impedance Z0. Matching
Rectangular waveguide. Cut off frequency. Energy flow.
Attenuation in guides.

6.  Other Sources of Radiation (3 lectures)

Bremmstrahlung
Cyclotron and Synchrotron Radiation
Cerenkov Radiation

Feedback will be offered by examples class tutors based on examples sheets, and model answers will be issued.

Bekefi, G. & Barrett, A.H. Electromagnetic vibration, waves and radiation, (MIT)
Grant, I. & Phillips, W.R. Electromagnetism, (MPS, Wiley, 2nd edition)
Smith, G.S. An Introduction to Classical Electromagnetic Radiation, (CUP 1997)