INSTRUMENT : PLASMA SCIENCE EXPERIMENT
SPACECRAFT : VOYAGER 1
Instrument Id : PLS Instrument Host Id : VG1 Principal Investigator : JOHN D. RICHARDSON Pi Pds User Id : JRICHARDSON Instrument Name : PLASMA SCIENCE EXPERIMENT Instrument Type : PLASMA INSTRUMENT Build Date : 1973 Instrument Mass : 9.900000 Instrument Length : UNK Instrument Width : UNK Instrument Height : UNK Instrument Serial Number : SN002 Instrument Manufacturer Name : MASSACHUSETTS INSTITUTE OF
The Voyager Plasma Science experiment consists of four modulated Grid Faraday Cups, three (A, B, C) of which are positioned about the Telemetry Antenna Axis and generally point toward the Earth with the fourth (D) at a right angle to this direction. Ion currents are sampled simultaneously in all four cups, electrons in the D-cup only. The instrument has an energy/charge range of 10-5950 V. Data is taken in four ways, high and low resolution ion modes and high and low energy electron modes with energy resolution varying between 3.6 and 29%. The integration time for each energy channel can be varied; 0.21 s/channel is used at Jupiter and Saturn.
Supersonic flow can be observed only when one of the detectors points within 45 degrees of the plasma velocity, subsonic flow is observed at all orientations. The current observations as a function of energy/charge allows determination of the plasma density, temperature, and velocity.
The objective of the Plasma Instrument is to characterize plasma conditions throughout the Voyager trajectory, in the solar wind, during the planetary encounters, and in the interstellar medium.
Each detector has an effective field of view which is a cone of half angle 45 degrees; the detector response falls off quickly at higher angles. Thus, for the instrument to measure ion parameters in a supersonic or transonic plasma some of the detectors must look into the