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Voyager 1 Hourly Plasma Parameters, Interplanetary Solar Wind


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

Time span: 1977-09-07 to 1980-12-31


This collection contains hourly average key parameters for interplanetary cruise data acquired by the Voyager 1 Plasma Science (PLS) experiment. The data are written in ASCII format and provided in files named V1_HOUR_yyyy.ASC, each covering one year of data for year "yyyy". The file V1_HOUR.FMT gives the data record format. Each key parameter record includes year, day, hour, proton speed (km/s), proton density (#/cc), proton thermal width (km/s), where proton temperature T(eV) = 0.0052(width)**2, and alpha density (#/cc), as well as proton bulk speed and vector components (Vr, Vt, Vn) in the RTN coordinate system. In RTN the R axis is outward from the Sun to the spacecraft, T is the cross product of the solar rotation axis and R, and N completes the orthogonal system. All parameters are derived from a nonlinear fit calculation. A parameter E1 (if present) gives the sum of currents for electrons.

These cruise data were obtained from the MIT Plasma Group's anonymous FTP site at and were accompanied by spacecraft SEDR ephemeris data cataloged at NSSDC under data set ID XXNO-00428.

The data are available on-line at

Alternate Names

  • 1-Hr Solar Wind Plasma Archive


  • Space Physics: Heliospheric Studies


  • 77-084A-06N

Additional Information



Questions and comments about this data collection can be directed to: Dr. John F. Cooper



NameRoleOriginal AffiliationE-mail
Dr. John W. BelcherData ProviderMassachusetts Institute of
Dr. John W. BelcherGeneral ContactMassachusetts Institute of
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