NSSDCA ID: 1981-070A-04
Mission Name: Dynamics Explorer 1The Retarding Ion Mass Spectrometer (RIMS) consisted of a retarding potential analyzer for energy analysis in series with a magnetic ion-mass spectrometer for mass analysis. Multiple sensor heads permitted the determination of the thermal plasma flow characteristics. This instrument was designed to operate in two basic commandable modes: a high-altitude mode in which the density, temperature, and bulk-flow characteristics of principally H+, He+, and O+ ions were measured; and a low-altitude mode that concentrated on the composition in the 1- to 32-u range. This investigation provided information on (1) the densities of H+, He+, and O+ ions in the ionosphere, plasmasphere, plasma trough, and polar cap (including the density distribution along the magnetic vector in the vicinity of the satellite apogee); (2) the temperature of H+, He+, and O+ ions in the ionosphere, plasmasphere, plasma trough, and polar cap (energy range 0-45 eV); (3) the bulk flow velocities of H+, He+, and O+ in the plasmapause, plasma trough and polar cap; (4) the changing character of the cold plasma density, temperature, and bulk flow in regions of interaction with hot plasma such as at the boundary between the plasmasphere and the ring current; and (5) the detailed composition of ionospheric plasma in the 1-to 32-u range. He++ and O++ were also measured. The instrument consisted of three detector heads. One looked out in the radial direction, and the other two were along the plus and minus spin-axis directions. Each detector had a 55-deg half-cone acceptance angle. The detector heads had a gridded, weakly collimating aperture where the retarding analysis was performed, followed by a parallel plate ceramic magnetic mass analyzer with two separate exit slits corresponding to ion masses in the ratio 1:4. Ions exiting from these slits were detected with electron multipliers. In the apogee mode, the thermal particle fluxes were measured while the potential on a set of retarding grids was stepped through a sequence of settings. In the perigee mode, the retarding grids were grounded and the detector utilized a continuous acceleration potential sweep that focused the mass ranges from 1 to 8, and 4 to 32 u. Time resolution was 16 msec. Additional details can be found in C. R. Chappell et al., Space Sci. Instrum., v. 5, n. 4, p. 477, 1981.
Questions and comments about this experiment can be directed to: Dr. Scott Boardsen
Name | Role | Original Affiliation | |
---|---|---|---|
Dr. George R. Carignan | Other Investigator | University of Michigan | carignan@engin.umich.edu |
Prof. Peter M. Banks | Other Investigator | Stanford University | pbanks@engin.umich.edu |
Prof. Andrew F. Nagy | Other Investigator | University of Michigan | anagy@engin.umich.edu |
Prof. William B. Hanson | Other Investigator | University of Texas, Dallas | |
Dr. John H. Hoffman | Other Investigator | University of Texas, Dallas | |
Dr. Charles R. Chappell | Principal Investigator | NASA Marshall Space Flight Center | rick.chappell@vanderbilt.edu |
RIMS page (NASA/MSFC) Access to data