Title: Correlated magnetic tail and radiation belt observations
Abstract: The Nasa Imp 1, or Explorer 18 satellite, has provided measurements of magnetic field strengths and directions out to a geocentric distance of 31.5RE (earth radii). As a result, the earth's magnetic field has been mapped out in great detail [Ness et al., 1964; Ness, 1965] in both the solar and antisolar directions. During the period of these measurements (November 1963 to May 1964) the APL satellite 1963 38C was sampling the trapped electron population at an altitude of 1100 km [Williams and Smith, 1965; Williams and Palmer, 1965]. The purpose of this note is to report simultaneous observations from the above two satellites during a magnetic disturbance in April 1964, showing the correlation between changes in the earth's magnetic tail and the radiation, belts within the magnetosphere.