Analysis of Electron Retarding Potential Analyzer Measurements of Vehicle Skin Potential in the Precede Experiment.

摘要

A 2kW electron accelerator was launched as the initial launch in the EXCEDE series of artificial auroral experiments. The launch,designated PRECEDE,was supported by a number of ground based optical systems to record the electron induced atmospheric emissions as a remote diagnostic technique of accelerator performance in addition to recording emissions of aeronomic interest in a controlled artificial aurora. The electron source,square wave modulated at 0.5Hz,was initiated at 95km on payload ascent and continued through apogee (120km) to a decent altitude of approximately 80km providing a total of 90pulses of the 2.5kV 0.8ampere electron beam over a period of 180seconds. A rocketborne retarding potential analyzer provided a measure of the vehicle potential due to a net positive charge build up on the electron emitting payload. A steady-state vehicle potential of less than 30volts was indicated at apogee with substantially smaller values at lower altitudes. Langmuir probe theory is shown to accurately model the altitude dependent steady-state vehicle potential.