------------------------------------------------------------ aareadme file at ftp/spacecraft_data/explorer/explorer35/plasma_probe/3-min_interplanetary_plasma_param/ ------------------------------------------------------------ This directory provides access to 1967 and 1968 files of 3-min plasma parameter data in ASCII format, from the MIT Faraday Cup flown on Explorer 35. This data set (Version 3) was created by GSFC's Space Physics Data Facility (SPDF) in 2010 as the culmination of a series of intermediate versions (V2, V1), the first of which was SPDF-created from an MIT- provided EBCDIC-formatted version. Versions 1, 2 and 3 are all ASCII. The main changes between the versions were: 0 -> 1. Change format from EBCDIC to ASCII 1 -> 2. Change time tagging (MMDD>DOY), add spacecraft position data 2 -> 3. Delete flow velocity data that were not aberration- corrected; delete engineering-oriented parameters; change flow angle sign conventions for consistency with other data; introduce Cartesian representation of flow velocity vector. The Version 1 and 2 data files are accessible from the "old" subdirectory of this directory. The format of the Version 3 ASCII data set is: Word number Format Description 1 I4 Year (1967,1968) 2 I4 Day of year(1-366) 3 I3 Hour of day (0 . 23) 4 I3 Minute of hour (0 . 59) 5 I3 Second of minute (0 . 59) 6 F6.1 Ion density (number/cc) 7 I4 Thermal speed (km/s) 8 I6 Flow speed (km/s) 9 F6.1 Flow longitude (deg) (see note below) 10 F6.1 Flow latitude (deg) (see note below) 11 I6 Vx(gse) km/s 12 I6 Vy(gse) km/s 13 I6 Vz(gse) km/s 14-16 3F8.3 S/C position X,Y,Z in GSE, Re 17-19 3F8.3 S/C position X,Y,Z in SSE, (see notes below) Note: The flow longitude angle, in degrees, increases positively (negatively) from zero as the flow direction changes away from the -Xgse axis toward the +Ygse (-Ygse) axis. The flow latitude angle, in degrees, increases positively (negatively) from zero as the flow direction changes away from the (X-Y)gse plane toward the +Zgse (-Zgse) axis. Note: The SSE (Selenocentric Solar Ecliptic) coordinate system has its X axis from the moon to the sun and Z axis normal to the ecliptic plane, positive northward. Components are given in units of lunar radii. (Note that the maximum directional difference between the unit vectors Xgse and Xsse is about 0.15 deg.) Note: The GSE and SSE position vectors were taken from the 81.92s- resolution Explorer 35 magnetic field data set accessible from https://spdf.gsfc.nasa.gov/pub/data/explorer/explorer35/ gsfc_magnetometer/82s_mag_data_ascii/. The position vectors we added to the 3-min plasma records had the first 81.92s time stamp following the 3m time stamp of the plasma record, as long as the former was not more than 3 minutes later than the latter. ---------------------------------------------------------------------