Global Map of Chorus Wave Sizes in the Inner Magnetosphere

Abstract

The dynamics of the radiation belts are largely affected by the resonant interactions of energetic particles with plasma waves, such as whistler mode chorus waves. These waves play a direct and crucial role in the acceleration and loss of radiation belt electrons. The properties of these waves have been investigated thoroughly using various missions that carried wave instruments within the inner magnetosphere. One of the most conspicuous properties of chorus waves is the size of the wave packets. Past studies have estimated the size of chorus wave packets as a function of radial distance, magnetic latitude, and geomagnetic activity. This study takes advantage of the comprehensive wave data from the Van Allen Probes mission to draw a global map of the size of chorus wave packets in the inner magnetosphere. Results show that the size of lower band chorus wave packets varies between ∼1,000 and2,000 km depending on the intensity and activity of chorus waves in the inner magnetosphere. In general, the largest chorus wave packets are observed on the dawn-dayside where chorus wave activity is also high. The results will help us better understand the interaction region and the generation mechanism of the chorus waves.