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Color Spectrograms


Availability: At NSSDC, Ready for Offline Distribution (or Staging if Digital)

Time span: 1987-01-01 to 1988-06-29


Each of the 35-mm slides, entitled MEPA ANGULAR DISTRIBUTION, covers a time span of one orbital period and contains two principal panels. These spectrograms provide directional fluxes of ions, in color code, averaged over fairly broad energy bands; one panel is assigned to each ionic species, and it is specified by time and angular sector numbers, 1-32. The fluxes are averages over 6.4 min. A pair of dotted curves specifies the sector numbers that contain 90-deg pitch angle fluxes. As labeled in each panel, the ionic species may be, irrespective of charge number, either H (energy band 56-190 keV), or He (72-240 keV and 680-1900 keV), or C-N-O group (137-365 keV and 910-2320 keV). There are three additional panels, without species discrimination (and, presumably, dominated by H+), covering the energy bands 34-50, 83-151, and 540-1000 keV. At the bottom of each slide is a slim panel that provides the smallest angle made by the viewing cone of the instrument with the magnetic field direction. Zero pitch angle fluxes are sampled only rarely. Another curve in the same panel provides the rms variation of the B-field magnitude during the averaging interval of 6.4 min. Each of the slides labeled MEPA PHA SPECTRUM provides intensities (counts/s) of atomic species, regardless of charge number, as a function of time of flight (over a 10 cm path) and energy, in color code. The intensity in each of the panels in a slide is an average over a few hours and a corresponding band of L-values, both of which are labeled on each panel. There are five tick marks on the energy axis and another five on the time of flight (TOF) axis. They are, from left to right, 50, 100, 500, 1000, and 5000 keV; and, bottom to top, 5, 10, 20, 50, and 100 ns. Each of the color coded sloping lines (or bands) pertains to one atomic species, irrespective of charge number. It is easy to ascertain the atomic species of each line by means of a pair of TOF (which contains velocity information) and energy values on the line. Each of the slides labeled MEPA ENERGY SPECTRUM provides in five separate panels the differential-energy fluxes, in color code, of (a) Fe, (b) C-N-O group, (c) He, (d) H, and (e) all ions, irrespective of mass. The fluxes are averages over a 6.4-min period. The pitch angle information contained in the sixth panel is often erroneous. Alongside the time axis are indicated the L-values and magnetic local times (MLT) of the spacecraft locations. These slides from the 84-088A-02 experiment are part of a composite data set that contains slides from the other two particle experiments, i.e., 84-088A-01 and 84-088A-03.

Alternate Names

  • Color Spectrograms, Slides


  • Space Physics: Magnetospheric Studies


  • 84-088A-02A

Additional Information



Questions and comments about this data collection can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Mr. Stuart R. NylundGeneral ContactApplied Physics
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