Explanatory notes:
The electron pitch-angle distribution averages included in this data set are
derived from integrating the electron pitch-angle distributions measured by the
Wind/SWE electron instrument (see Ogilvie et al., "SWE, a comprehensive plasma
instrument for the Wind spacecraft", Space Sci. Rev., 71, 55, 1955). Averages
of phase-space density (f) over key regions of the unit sphere (the set of all
possible electron velocity directions) are computed from 3s measurements which
are spaced either 6s or 12s in time. These quantities are reliable and citable
with caution, meaning that the PI advises that the user should discuss their
interpretations with a member of the SWE science team before publishing.
The following comments are intended to aid in the use and interpretation of the
averages reported in this data set. We begin this analysis with a measure of f
for each pitch-angle bin, six degrees in width, from 0 degrees (flux nearly
parallel to B) to 180 degrees (flux nearly anti-parallel with B). The f values
for pitch-angles from 0-90 degrees (parallel streaming) are integrated (with
angluar weighting and assumptions of gyrotropy) over this half-sphere, then
averaged by dividing out the 2-pi solid angle of the half-sphere; the result
being referred to as the 'f_para' average. Similarly, the 'f_perp' (flux nearly
perpendicular to B) average is the result of integrating f for pitch-angles from
60-120 degrees (a region also 2-pi in solid angle). Next, the 'f_anti' (flux
nearly anti-parallel to B) average covers the half-sphere of "backward"
streaming electrons; having pitch-angles from 90-180 degrees. Finally, the
'f_omni' (omni-directional) average provides the integral of f over the full
sphere, divided by the full 4-pi solid angle; providing a measure of total
electron flux into the region of observation.
The above analysis is carried out for each of 16 energy channels ranging from
about 10 eV to as much as 3 keV. The exact energies at which observations are
made is time-varying, and this data set reports the electron speeds each channel
observes (|V|, in cm/s, along with the observations themselves) at any time.
Hence the data set reported here contains: f_para, f_perp, f_anti, f_omni (for
each of 16 values of |V|), and the 16 values of |V| (time-varying, although
usually much more slowly than the order of a day).