Polar Cap/polar cusp studies using incoherent scatter radar facilities

The application of incoherent scatter radar for polar cap and cusp studies is briefly discussed and recent investigations with the Sondrestrom radar of plasma convection in the very high latitude ionosphere are reported. It appears that the sunward convection at auroral latitudes turns anti-sunward toward high polar latitudes over a considerable range of local time around noon, and that there is little evidence of a narrow throat through which the bulk of sunward plasma convection is channeled into the polar cusp. It is also found that the predominant east-west convection poleward of the dayside convection reversal region depends on the IMF-By component, and that the IMF-Bz component affects convection in a wide latitude range probably in all local time sectors. The time lag between the occurrence of an IMF change at the front of the magnetopause and the corresponding change in the convection is at the most 15-20 minutes