Correlation of changes in the outer-zone relativistic-electron population with upstream solar wind and magnetic field measurements

A study has been made of the correlation of the population of relativistic electrons in the outer-zone magnetosphere with the properties of the solar wind (speed, density, magnetic field) during a solar minimum period, The study is based upon observations made in the Spring of 1995 with sensors aboard 1994-026 and WIND. It is found that a large relativistic electron enhancement depends upon a substantial solar-wind speed increase associated with precursor solar-wind density enhancement, and, in particular, upon a southward turning of the interplanetary magnetic field.