Ionosphere Measurements During Cassini's Earth Fly-by
During the Earth flyby, nine of the twelve scientific instruments on Cassini
turned on to gather data on the Earth/Moon system. The Huygens Probe and its
six scientific instruments remained dormant during the Earth fly-by.
In outline, the fly-by timeline was
Magnetometer boom deployment: ~07 UT 16 Aug
Inbound bow shock/magnetopause crossing (approx subsolar): ~02 UT 18 Aug
Closest approach: ~03 UT 18 Aug
Outbound magnetopause crossing (at ~75 RE downtail on dawn flank):
~12 UT 18 Aug
Outbound shock crossing (between ~175-275 RE downtail on dawn flank):
~2-12 UT 19 Aug
Crossing of Earth's distant tail/wake region (~7000 RE): ~9-19 Sept
During the Earth flyby, the Sondrestrom incoherent scatter radar measured
high-latitude ionosphere. The radar was operated between 00 UT and 15 UT on
18 August to measure F-Region Convection, Hall and Pedersen Conductivity,
Electron temperature at different altitudes, Ion temperature at different altitudes,
among other fundamental measurements.
along magnetic meridians parallel to Sondrestrom's were used
to measure these parameters over 3 degrees invariant latitude in the E-region and
9 degrees in the F-region. Below are clockdial plots of the measurements.