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Magnetic Field Vector SFDU Data


Availability: Archived at NSSDC, accessible from elsewhere

Time span: 1984-08-18 to 1988-08-26


These 68-s averages of magnetic field data are written on magnetic tape in SFDU format. Each physical block has a fixed length of 12,288 bytes, written in English/ASCII and VAX binary representation. The volume header file provides an outline of the content and structure of entries. It is followed by an ephemeris file of many blocks, which includes data on GSE Cartesian components of the spacecraft's location and velocity, its latitude and longitude, Cartesian components of the magnetic field, SM latitude and local time of the spacecraft, and local time of the subsatellite point, each listed every 5 min. Written next is an attitude file that includes the right ascension and declination of the direction of the spin axis, and the spin rate, listed once every orbit. It is followed by an "events" file that includes information on maneuvers, data gaps, anomalous conditions, etc. The final sequence of files contains the magnetic field data, written as one file per day of data. Each logical record of 80 bytes provides time, 68-s averages of GSE and GSM Cartesian components of the field (nT), and standard deviations along and perpendicular to the spin axis. Also provided are components, along and perpendicular to the spin plane, of wave amplitudes (volts) in the 5-50 Hz band. The header of each file provides all necessary information about data content, format, units, etc., so that little or no external documentation is needed to extract data of interest.

Data are available online at

Alternate Names

  • Magnetic Field Vector SFDU


  • Space Physics: Magnetospheric Studies


  • 84-088A-05B

Additional Information



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



NameRoleOriginal AffiliationE-mail
Mr. Robert M. CandeyGeneral ContactNASA Goddard Space Flight
Dr. Thomas A. PotemraGeneral ContactApplied Physics Laboratory
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