Air Force Geophysics Laboratory, Technical Report AFGL-TR-88-0195, 1988.

Scientific Background and Design Specifications for a Near−Earth Heliospheric Imager

B.V. Jackson
University of California, San Diego, La Jolla, CA


This report is intended to define the instrument specifications for a heliospheric imager capable of observing transient, diffuse features in the heliosphere from a spacecraft near 1 AU. These features include coronal mass ejections, co-rotating density enhancements, shock waves and any other disturbances that can affect the intensity of the electron-scattering coronal brightness. Our technique of imaging a large portion of the heliosphere using the HELIOS spacecraft zodiacal-light photometers has shown that it is possible to measure the structures around a spacecraft and to make good measurements of material in and out of the ecliptic plane. The HELIOS data show that is is posible to determine the velocityes and spatial distributions of the large-scale features which propagate into the heliosphere. The instrumentation may be regarded as a successor to the zodiacal-light photometers of the HELIOS spacecraft. Such a second-generation instrument based on these principals could make effective use of in situ solar wind data from spacecraft in the vicinity of the imager, and would allow study of the effects of heliospheric structure interaction with the magnetosphere as never before possible. In addition, the imager would allow up to three days warning of the arrival of a mass ejection at Earth from the Sun.