Norwegian-Canadian Svalbard Expedition, winter 1975

Extract

Current theories and observations in magnetospheric physics suggest that low-energy particle fluxes, exhibiting the characteristics of solar-wind particles, have direct access to certain regions of the high-latitude polar ionosphere (Akasofu and Lanzerotti, 1975). The precipitation of these particles occurs over a few degrees of latitude and several hours of magnetic time (centred on geomagnetic noon) and this region has been termed the dayside magnetospheric cleft (Vasyliunas, 1974). The resultant phenomena, such as dayside auroral emissions, have not been extensively studied due to the rather remote location of accessible land mass at latitudes high enough for observations at local apparent noon to be made (Fig 1). Magnetospheric cleft observations have been carried out from instrumental aircraft (Whalen and Pike, 1973) and from Cape Parry, NWT (Peterson and Shepherd, 1974) in previous winters. Aircraft observations are, obviously, of limited duration and twilight at Cape Parry severely restricts photometric observations.