Velocity moments of these averaged distribution functions were
integrated to obtain the ion number density and flow velocity:
The number density is plotted in the second panel and the magnitude of the flow velocity is shown in the third panel. The polar angles of the flow velocity, ø (ø = 180° is anti-sunward) and ( is the S/C spin plane) are plotted in the fourth panel.
The kinetic temperature was computed from the distribution function by
integrating:
The CPI solar wind ion analyzer is an E/Q analyzer and the initial
distribution functions were calculated assuming that the plasma is
H^{+}. Care must be taken when multi-component plasmas are
present. If He^{++} is present and is flowing with the same
speed as the H^{+} component, it will contribute to the
distribution function at twice the velocity (four times the energy) of
the H^{+}. To facilitate the automated processing of these data
the above integral was evaluated between
|v_{min}| = 171 km/s and
|v_{max}| = 1.35 ×
|u|. The resulting temperatures produce excellent fits
to the observations. When He^{++} is present the distribution
functions are consistent with an He^{++} temperature,
T_{He++} = 4 × T_{H+},
i.e., the H^{+} and He^{++} have similar thermal
velocities.