Get access

Coordinated measurements of auroral zone plasma enhancements


  • E. J. Weber,

  • R. T. Tsunoda,

  • J. Buchau,

  • R. E. Sheehan,

  • D. J. Strickland,

  • W. Whiting,

  • J. G. Moore


The Air Force Geophysics Laboratory's Airborne Ionospheric Observatory (AIO) performed radio, optical, and scintillation measurements on a series of north-south flight legs along the Chatanika radar magnetic meridian. The incoherent scatter radar was operated in a north-south magnetic meridian scan mode to measure ionospheric parameters (electron density, temperature, and ion drift) from 600 km north to 600 km south of the radar and from ∼80 to 700 km altitude. Ionospheric structure measured by the radar is compared with remote optical and ionosonde measurements from the AIO and with precipitating electron characteristics measured by a Defence Meteorological Satellite Program satellite. Long-lived F region plasma enhancements (plasma blobs) were observed during this experiment. From the simultaneous measurements it is shown that these enhancements were not locally produced by precipitating particle fluxes. F region electron concentrations, calculated from simultaneously observed precipitating electron fluxes, are significantly less than those observed in the plasma enhancements. These premidnight features (plasma blobs) were in fact observed to be convecting sunward (to the west) at a few hundred meters per second and are thus presumed to have been produced well upstream in the convection flow within a region of significantly greater production rate. Intense scintillation of satellite signals due to ionospheric irregularities is generally confined to these regions of enhanced F region density. Simultaneous measurements of independent parameters identifying the auroral E layer (1–20 keV precipitating electrons, 4278-Å N2+ emission, f0E, and radar electron densities) all agree well as to location and the latitude profile of the auroral E layer and associated diffuse aurora.

Get access to the full text of this article