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Solar Wind Ion Moments Crossed-Fan Analyzer (July-Dec) 24/48-Sec N,V,T Data


Availability: Archived at NSSDC, accessible from elsewhere

Time span: 1977-10-30 to 1984-01-30


This data set consists of solar wind ion moments derived from measurements obtained by the crossed-fan electrostatic analyzers of the Solar Wind Ion Experiment. The data cover the solar wind seasons (July through December) only; the data are not useful elsewhere along the orbit. The time resolution is 24 seconds (high data rate) or 48 seconds (low data rate). Each data record contains the date (YYMMDD); Universal Time in seconds of the day as well as in hours, minutes, and seconds; the proton density (per cm**3), bulk flow speed (Km/sec), flow azimuth (degrees, with zero degrees corresponding to flow from the sun [corrected for aberration] and positive azimuths corresponding to flow toward dawn), flow latitude (degrees, with positive latitudes corresponding to flow toward the south), the minimum proton temperature (Kelvins), and the alpha/proton fraction (alpha fraction = 0.00 means no determination made). The density values have not been cross-correlated with those from other experiments. The ion experiment had degraded by April 1980 and the density values in later years are suspected to be too low. Many of the measurements were obtained within the foreshock region where the solar wind flow is affected by the waves present there. To protect the instrument, this experiment was turned off whenever the spacecraft was below 30,000 km. The Fast Plasma Experiment (FPE) detectors had degraded by January 1978, and it was not felt worth the effort to archive those data.

Data are available online at

Alternate Names

  • SW Ion Moments X-Fan Anal. 24-Sec


  • Space Physics: Magnetospheric Studies
  • Space Physics: Heliospheric Studies


  • 77-102A-01N

Additional Information



Questions and comments about this data collection can be directed to: Dr. H. Kent Hills



NameRoleOriginal AffiliationE-mail
Dr. John T. GoslingGeneral ContactLos Alamos National
Mr. Robert M. CandeyGeneral ContactNASA Goddard Space Flight
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