Chorus Element Properties: Statistics From Automated Chorus Detection

Abstract:

Using novel signal processing techniques, we have developed autonomous algorithms that can analyse Van Allen Probes waveform observations to determine the characteristics of individual chorus elements. In particular, the methods allow us to determine the frequency/time sweep rate of chorus elements for a large number of events without the need for manual identification of the elements. This enables statistical studies of the properties of the individual chorus elements which has been limited in the past to small numbers of events identified and analysed by hand. We present the basics of the automated detection technique and show results of the statistics on the range and character of chorus element sweep rate. In addition we show how chorus power varies with radial position, magnetic latitude, and magnetic local time as well the relation between chorus power and sweep rate.