Published online by Cambridge University Press: 14 August 2015
An overview is given of various phenomena observed by numerous spacecraft in the interplanetary medium. These phenomena are related to transient solar events such as flares and coronal holes. The effects of such transient solar events are extensive. At times, a solar event can affect the interplanetary medium out to distances as far as 17.2 AU and over a wide range of azimuthal angles. Also some phenomena, such as high frequency fluctuations (precursors of shocks) in the interplanetary medium, appear beyond 1 AU. Thus, transient phenomena are significantly modified by their passage through this medium. The conclusion is reached that transient events originating on the sun and passing through the interplanetary medium represent complex and significant physical problems.