Plasma Probe

Description

A split-collector Faraday cup mounted on the spacecraft equator was used to study the directional intensity of solar wind ions and electrons. The following 25-s sequence was executed three times for ions and once for electrons each 328 s. Twenty-seven directional current samples from the two collectors were taken in the energy per charge (E/Q) window from 80 to 2850 eV. The currents in the two collectors were then sampled in eight E/Q windows between 50 and 5400 eV at the azimuth at which peak current appeared in the previous 27 measurements. Due to telemetry limitations, only the following data were returned to earth every 328 s: for ions, the sums of currents measured on the two collector plates twice and the difference once, and for electrons, the sums once. The experiment worked well from launch until the final spacecraft data transmission. For further details, see Lyon et al., J. Geophys. Res., v. 72, p. 6113, 1967.