00readme.txt

This directory contains one daily-resolution file and several
hourly-resolution files containing "impact parameters" for
the six pairings of the four bodies: Earth, IMP 8, Wind and
ACE.

The "impact parameter" is the distance by which a plasma
element moving radially away from the sun with a speed
of 390 km/s, observed at an upstream spacecraft, would
miss intercepting a downstream spacecraft (or Earth),
allowing for the 30 km/s motion of the Earth and its nearby
spacecraft about the sun.

Input data were spacecraft position vectors from SSCWeb.
The algorithm used for the impact parameter (D) for the
i-j pair of bodies was

Dij = SQRT {[Yi-Yj+(Xi-Xj)/13]**2 + (Zi-Zj)**2}

The Impact Parameter for a given day in the daily file is
taken as that for the first hour of that day in the hourly file.

The format of the records (including inter-word blanks) is:

Year            I*4          1994, ...
Day of year     I*4        1...365
Hour            I*3         0...23    (not included in daily-res file)
Diw             F7.1
Die             F7.1        D's are in units of earth radii
Dwe             F7.1
Dai             F7.1        e,i,w,a = Earth, IMP, Wind, ACE
Daw             F7.1
Dae             F7.1
----------------------------------------------
R. Parthasarathy, N. Papitashvili, J. King
November 7, 2002