A simulation study of the propagation of whistler-mode chorus in the earth's inner magnetosphere

摘要: Whistler-mode chorus emissions are generated in the region close to magnetic equator outside plasmapause during geomagnetically disturbed periods. Spacecraft observations near have revealed that appear frequency range from 0.2 0.8 Ω e0 , where is electron gyrofrequency at equator, while of classified into lower-band (0.2 0.5 ) and upper-band (0.5 by a distinct gap [1]. Observations typically propagate along field line its source become oblique their propagation away equator. Propagation properties been studied for half century (e.g., [2,3]). Theoretical estimations results ray-tracing studies compared with space high-latitude ground stations. In present study, we study whistler-mode magnetosphere spatially two-dimensional simulation code dipole coordinates [4]. We set system so as assume plasmapause, corresponding radial distance 3.9 4.1 R E equatorial plane latitudinal −15 +15 degrees, Earth's radius. model element propagating northward L=4 rising tone 0.7 time scale 5000 −1. For initial density distribution cold electrons, three types conditions plasmapause: without duct (Run 1), enhancement 2), decrease 3). Run 1, result reveals waves different wave ray-path Runs 2 3, propagates inside assumed changing normal angle. The show reveal resultant spectra observed between cases. spectral modification effect should play significant role precipitation energetic electrons related pulsating aurora through interaction magnetosphere, particularly clarifies variation be taken account thorough understanding resonant interactions inner magnetosphere.