Solar and heliospheric geoeffective disturbances

The past decade has brought advances in several areas of solar-terrestrial physics which, when combined, provide nearly all of the pieces necessary for predicting geomagnetic storms. Advances in techniques for observing the Sun in X-rays and white light allow identification of solar disturbances headed toward Earth. Advances in our understanding of how the resulting heliospheric disturbances reflect aspects of the Sun's magnetic field allow predictions of their magnetic topology and, hence, provide some measure of the geoeffective southward component which they carry. Advances in our understanding of the relationship between transient heliospheric disturbances and high-speed streams and how storm strength depends upon solar wind density and the magnetic polarity of streams allow substantial refinement for prediction schemes. (C) 2000 Elsevier Science Ltd. All rights reserved.