First direct measurement and characterisation of plasma waves, originating from outer space, in the polar upper atmosphere, achieved in the Larsemann-Vestfold region by winter traverses onto the icecap

Abstract

The geomagnetic field focuses onto the polar regions near the auroral oval, which the Larsemann Hills are in proximity to. Solar disturbances cause instabilities in the geomagnetic field and the associated electrically-charged particle (plasma) population, which translate into waves that propagate along geomagnetic field lines towards the Earths polar regions. As the waves enter the electrically charged upper atmosphere (ionosphere) they convert to a mode that propagates parallel to the Earth's surface in a waveguide. Hence, energy from outer space is distributed into the polar atmosphere, particularly near the auroral oval. A series of winter vehicle traverses in the Larsemann-Vestfold region deployed and operated a sensor array, with international co-operation, to measure and characterise the waveguide for the first time at polar latitudes. The directions of areas of origin for the plasma waves and propagation properties could be assessed using the array, not previously possible at permanent stations. Similar waves from sources equatorward of the auroral oval have been recently observed by new radar techniques, which could also be employed at high-latitudes, where the waves have recently been shown to affect the lower atmosphere.