Polar patches and the “tongue of ionization”


  • D. P. Steele,

  • L. L. Cogger


Optical images of [O I] 630.0-nm emission from drifting F region polar patches acquired with a sensitive all-sky imager have been analyzed to infer the ionospheric convection velocity over a period of 9 hours on December 8, 1993. The drift vectors agree well in both direction and magnitude with simultaneous measurements from a nearby digital ionosonde. The delay between interplanetary magnetic field By changes measured at IMP 8 and changes in the convection direction at the pole is estimated. A montage of the optical emission from the patches observed over the period is presented to illustrate the range of optical patch shapes, sizes, and spacings observed.