Fig. 2.

An example of counts recorded by SLED in Channel 4 of Te-1 (0.6–3.2 MeV) on 13 March, 1989 (00:00–08:00 UT) while traversing a circular planetary orbit. The coordinate system is MSO: +x sunward direction, +z to the north ecliptic pole, +y completes the right handed system. The look direction of SLED is indicated at the top/right. Mars is represented at the centre of the plot. The relative number of counts recorded along particular orbits is indicated by the magnitude of lines that represent the individual readings made at successive locations. These lines are drawn from points along the orbital path in a direction perpendicular to that path. Gaps correspond to operational switch off times or loss of data and the depression is due to particle shadowing. The two dotted lines behind Mars indicate the location of the solar wind flow shadow caused by the main H⁺ population in the solar wind near ~1 keV.