One of the mass-resolved files contains velocity moments up to second order for H+, He++, He+, and O+ ions, calculated two different ways (using different assumptions) and covering the energy ranges 10 eV/e - 100 eV/e (density only) and 100 eV/e - 16 keV/e. Each moment has a standard deviation associated with it, based on the propagation of counting statistics. This is the principal file providing relative ion composition ("MD-file").
The second file ("MC") contains spin-averaged energy spectra of the same four ions plus O++ ions, covering the energy range 10 eV/e - 18 keV/e in 32 energy channels, as well as information about the peak count rate in each channel. This information includes the time (in seconds) and spin angle of the peak, the maximum rate, and the angular range of count rates greater than 1/3 of the maximum rate ("full peak width at 1/3 of maximum"). This is the best file to use for studying the composition and probable origin of ion beams or flows, for example.
The third file ("MS") contains mass spectra in four energy ranges, whenever the instrument cycle included complete scans of the mass-per-charge range (from less than 1 amu/e to about 150 amu/e). Most cycles did include at least a few such scans at selected energies.
The "total ion" file ("ED") contains velocity moments up to second order as well, assuming that the counts are due entirely to H+ ions, but only for the 100 eV to 16 keV range. Since H+ ions usually dominate the count rate (proportional to the square root of charge/mass at given energy), this file typically provides an approximate and nearly continuous measure of the H+ at higher time resolution.
These ASCII files with numbers (NSSDC index 77-102A-12I) are complemented with hardcopy plots (NSSDC index 77-102A-12J) showing selected moments as a function of time, including the total ion pressure perpendicular to the local magnetic field, as well as the magnetic pressure and field direction angles.
The 28-month data set currently existing in this format at the NSSDC and at Lockheed occupies 545 megabytes and resides on six standard 6250 bpi half-inch 9-track magnetic tapes produced with the VAX/VMS backup procedure. A subset of these data is usually kept on computer disk (Dec VAX) at Lockheed, consist- ing of all the "ED-" and "MD-files", along with abbreviated versions of the "MC-files", called the "PF-files". The latter only contain data from three energy channels per ion, those with the highest, second highest, and third highest count rates.
For occasional small data requests a User may contact:
Dr. O.W. Lennartsson Lockheed Missiles & Space Company, Inc. Research and Development Division O/91-20, B/252 3251 Hanover Street Palo Alto, CA 94304 USA /Tel: (415) 424-3259; Fax: (415) 424-3333; SPAN: LOCKHD::LENNFor larger requests, please contact the NSSDC (at NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA). The NSSDC has been furnished with VAX/VMS command procedures for easy transfer of any number of days of data from tape to disk and subsequent transfer to new tapes using the more uni- versal COPY procedure.