Remote sensing and modeling of energetic electron precipitation into the lowerionosphere using VLF/LF radio waves and field aligned current data

[摘要] A model for the development of electron density height profiles based onspace time distributed ionization sources and reaction rates in the lowerionosphere is described. Special attention is payed to the definition of anauroral oval distribution function for energetic electron energy input intothe lower ionosphere based on a Maxwellian energy spectrum. The distributionfunction is controlled by an activity parameter which is defined proportionalto radio signal amplitude disturbances of a VLF/LF transmitter. Adjusting theproportionality constant allows to model precipitation caused VLF/LF signaldisturbances using radio wave propagation calculations and to scale thedistribution function. Field aligned current (FAC) data from the new Swarmsatellite mission are used to constrain the spatial extent of thedistribution function. As an example electron precipitation bursts during amoderate substorm on the 12 April 2014 (midnight–dawn) are modeled along thesubauroral propagation path from the NFR/TFK transmitter (37.5 kHz, Iceland)to a midlatitude site.

[学科分类] 电子、光学、磁材料