资源环境科技发展态势分析平台

Electrostatic electron cyclotron harmonic (ECH) waves can yield diffuse aurora primarily at higher L-shells by driving efficient precipitation loss of plasma sheet electrons. Here using the Van Allen Probes high resolution data, we examine in detail the global occurrences of ECH waves during the period from 1 October 2012 to 30 June 2017 and find that there are totally 419 events of enhanced ECH waves. The statistical results demonstrate that ECH waves can be present over a broad region of L = 4-6 and 00-24 MLT, with a higher occurrence in the region of L = 5-6 and 06-19 MLT. The electron phase space density exhibits a distinct ring distribution (partial derivative f/partial derivative v(perpendicular to) > 0) with the peak energy around a few kiloelectron volts. Both ECH wave events and the electron ring distributions are closely related and tend to be more distinct with increasing geomagnetic activity.