Gwybodaeth Modiwlau

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 ionosphere. Active research continues to study ionospheric plasma processes in terms of solar-terrestrial interactions, 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 coupling of the solar wind to the Earth's magnetoshpere is discussed and the consequences on the ionosphere described.

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. Production and loss mechanisms, ionospheric chemistry, servo-theory of the F-region..

Radiowave Propagation: Plasma frequency, gyrofrequency, phase velocity, group velocity, refractive index. Measurement techniques and an introduction to ionospheric radio physics.
The High-Latitude Ionosphere and the Magnetosphere: Magnetoscopic regions. Geomagnetic field; dipolar and distorted. Motion of charged particles; gyro, bounce and drift motion. Soalr wind-magnetosphere coupling; magnetic reconnection. Plasma convection. Electric currents; Pedersen, Hall, field-aligned. High-latitude ionosphere coupling to Magnetoshpere, auroral electrojets, geomagnetic substorms, aurora.