Relationship between long-term phase advances in high-latitude VLF wave propagation and solar energetic particle fluxes


  • Herbert H. Sauer,

  • Walther N. Spjeldvik,

  • F. Kenneth Steele


Anomalous advances of OMEGA VLF navigation system (10.2-kHz) signals during three extended periods (totaling 60 days) of solar cosmic ray event activity during 1982 are examined and compared with energetic proton, alpha particle, and electron precipitation into the polar cap ionosphere. Time profiles of the OMEGA 10.2-kHz Hawaii-to-Norway path phase advance are found to be almost congruent with the time profiles of the logarithms of the energetic proton fluxes precipitating into the polar cap as determined from instruments aboard the polar orbiting NOAA-6 satellite and the GOES-2 geostationary satellite. Although both energetic alpha particles and electrons contribute to the anomalous phase advance experienced by the 10.2-kHz Hawaii-to-Norway OMEGA signal, a simple, empirical algorithm reasonably relates the observed phase advance to the observed differential fluxes of 6-MeV solar cosmic ray protons.