A simple model of the auroral kilometric radiation visibility

Abstract

Examples of data collected with Polrad swept frequency analyzer during almost 2.5 years of Interball-2 mission are used to demonstrate directivity properties of the auroral kilometric radiation (AKR) observed in the Northern Hemisphere. In contrast to the previous, mostly statistical studies, single dynamic spectra have been analyzed. Simple modeling of AKR source visibility from the location of the observer reproduces the overall form of the dynamic spectrum with a single set of AKR source parameters valid during up to tens of minutes. Cases of filled and partially filled emission cones as well as smaller emission cones embedded in the main cone are found. Anisotropic AKR beams as thin as 10° and sometimes narrower are consistent with our model. Copyright 2005 by the American Geophysical Union.