General | MGF | EFD | LEP

  • Before you access the database, you should carefully read the following caveats.
  • Data are mostly reliable. But, if you have any questions or any difficulties about the data, please send them to the principal investigators.

Available Dates

  • Magnetic field data (MGF): From 18 September 1992 through 31 December 2019.
  • Electric field data (EFD): From 18 September 1992 through 31 December 2005.
  • Ion moment data (LEP): From 18 September 1993 through 31 December 2019.


  • The Geotail satellite has two editors onboard: The Editor-A data are only acquired with the real-time operation in Usuda Deep Space Center (UDSC) or Uchinoura Space Center (USC), Japan, while the Editor-B data are continuously recorded in the onboard tape recorders for 24 hours and are dumped to the NASA JPL Deep Space Network (DSN) stations.

Magnetic Field Data (MGF)

  • As of February 1 2008 the Bz component of the magnetic field has been corrected in the DARTS data set. The secular variation of the Bz offset value is shown in Figure. The ASCII files of daily Bz offset values are download from here.

Electric Field Data (EFD)

  • The present data are a preliminary version. Please contact PI if you have questions about the data quality.
  • EFD-P does not measure the electric field component parallel to the spin axis.
  • The Ex and Ey components in downloaded ASCII files are in satellite coordinates, which are nearly equivalent to GSE coordinates.
  • The Ex component should not be used because of the offset due to photoelectrons.

Ion Moment Data (LEP)

  • You should use the Editor-A dataset (when available) rather than the Editor-B dataset, since ion moments in the Editor-A data are more reliable. (Ion moments in the Editor-B are calculated onboard.)
  • The ion energy analyzer (LEP-EAi) has two energy scan mode: RAM-A (60 eV to 40 keV) and RAM-B (5 keV to 40 keV). RAM-B is selected to protect the very sensitive detector from intense low energy fluxes that are usually seen in the solar wind and magnetosheath. The energy scan mode is automatically selected onboard depending on incoming ion fluxes. At present, only the ion moments in the RAM-A mode are plotted/listed for the LEP-EAi data. (The LEP-EAi moments are presented by the solid lines in the plot.)
  • The ion moment data of the solar wind analyzer (LEP-SW) should be used only qualitatively. The LEP-SW ion moments are plotted/listed when the energy scan mode of LEP-EAi is RAM-B. (The LEP-SW moments are presented by the dotted lines in the plot.)

Last Modified: 11 August 2020