Quiet-time electron increases: a measure of conditions in the outer solar system

A possible explanation for quiet-time electron increases, increases in the intensity of 4-12 MeV interplanetary electrons that have been reported by Simnett, Cline, and McDonald, is discussed.It is argued that the electrons in quiet-time increases are galactic in origin, but that the observed increases are not the result of any variation in the modulation of these particles in the inner solar system.It is suggested instead that quiet-time increases may occur when more electrons than normal penetrate a modulating region that lies far beyond the orbit of earth.The number of electrons penetrating this region ma y increase when field lines that have experienced an unusually large random walk in the photosphere are carried by the solar wind out to the region.As evidence for this increased random walk, it is shown that five solar rotations before most of the quiet-time increases there is an extended period when the amplitude of the diurnal anisotropy, as is measured by the Deep River neutron monitor, is relatively low.Five rotations delay time implies that the proposed modulating region lies at -30 AU from the Sun, assuming that the average solar wind speed is constant over this distance at 400 km/sec.The implications for the correlation between periods of low amplitude diurnal anisotropy and quiet-time increases on interplanetary conditions out to-30 AU, and some possible models for the proposed modulating region are also considered.