|| PH39010 |
|| IONISED ATMOSPHERE |
|| 2004/2005 |
|| Dr Andrew R Breen |
|| Semester 2 |
|| Dr Andrew R Breen, Dr Eleri Pryse |
|| PH29010 , Core Physics Modules at Level 2 |
| Course delivery
|| Seminars / Tutorials || 2 seminars/tutorials |
|| Lecture || 20 lectures |
|Assessment Type||Assessment Length/Details||Proportion|
|Semester Exam||2 Hours end of semester examination for BSc students ||100%|
|Semester Exam||3 Hours end of semester examination for MPhys students ||100%|
After taking this module students should be able to:
describe the general behaviour of the ionosphere and the magnetosphere under normal conditions
outline the principles of propagation of radiowaves in an ionised medium
describe the motion of changed particles in a magnetic field
understand the concept of magnetic mirrors, magnetic bottles and loss cones, and magnetic reconnection
understand the concepts of magnetic substorms and aurorae
explain the behaviour of the high latitude ionosphere in terms of the mapping of magnetospheric processes
The presence of ionisation in the upper atmosphere was postulated to account for long distance radio wave propagation. Subsequent research established the existence of the ionised atmosphere and investigated its morphology. Active research continues to study ionospheric behaviour, in particular at high latitudes where the aurorae are a spectacular optical manifestation of incoming particles from space.
The morphology of the ionosphere is described, the production and loss processes of ionisation under normal conditions are explained, and the effects of neutral winds and electric fields are considered. An introduction is given to the influence of the ionosphere on radiowaves. The high latitude ionosphere is decribed in terms of magnetosphere processes mapped down the geomagnetic field.
Introduction: The ionosphere at mid and low latitudes: D, E and F regions, ionisation production and loss mechanisms, Chapman layers. Observed behaviours of the mid latitude ionosphere and the equatorial ionosphere. Motions of charged particles: effects of the neutral-air wind electric field.
Radiowave Propagation: Plasma frequency, gyrofrequency, phase velocity, group velocity, refractive index. Applications of the Appleton equation, ionosondes, transionospheric propagation.
The High-Latitude Ionosphere and the Magnetosphere: the high-latitude ionosphere as a map of processes in the magnetosphere; the precipitation of energetic particles and the aurora; magnetospheric electric fields and the eastward and westward electrojets; magnetic perturbations in the auroral zone.
** Reference Text
R.D. Hunsucker Radio Techniques for Probing the Terrestrial Ionosphere
J.K. Hargreaves The Solar-terrestrial Environment
Cambridge University Press
K. Davies Ionospheric Radio
Peter Peregrinus Ltd. for IEE
M.G. Kivelson and C.T. Russell (Eds) An Introduction to Space Physics
Cambridge University Press
May Britt Kallenrode (2001) Space Physics
W. Baumjohann and R.A. Treumann (1997) Basic Space Plasma Physics
Imperial College Press
B. Hultqvist, M. Oierostt, G. Paschmann & R. Treumann (eds) (1999) Magnetospheric Plasma Iounces and Losses
Space Science Reveiws, Vol 88
This module is at CQFW Level 6