Detection and Characterization of Chorus Elements in the Van Allen Radiation Belts Using SNR Maps

More than 99 percent of the visible universe is composed of plasma so improving our understanding of how particles interact with plasma waves in the Van Allen radiation belts is important to furthering our knowledge about the universe. The EMFISIS instrumentation suite on board the Van Allen Probes measures wave electric and magnetic fields in the radiation belts. Of particular interest are chorus waves which are thought to energize electrons in the radiation belts. Methods from geometric signal processing, image processing, and pattern recognition allow individual chorus elements to be characterized by their dominant angle (sweep rate), power and microstructure of the wave signature. These techniques can be used to automatically identify chorus waves and distinguish chorus waves from hiss-like chorus background noise. These techniques allow investigation of chorus properties across the terabytes of chorus data collected by EMFISIS.

We describe a technique capable of automated detection and characterization of individual chorus elements for a given signal-to-noise ratio using data collected by the EMFISIS suite. Multiple case studies will be discussed along with a statistical analysis of our findings and the relationship of detected elements with existing metrics.