Polar cusp, plasma mantle particles and their relationships to polar rain

摘要

On the basis of low altitude DMSP satellite particle data, characteristics of polar rain, cusp and plasma mantle are examined during the asymmetric polar rain enhancement period. Obtained results are summarized as follows : (1) From the comparison between number flux of cusp and polar rain precipitations, the cusp flux does not increase correlatively with the increasing of polar rain flux. This result suggests that sources of precipitating particles are quite different from each other. (2) Low energy pulsive electrons (plasma mantle) are occasionally observed in the polar rain region. These plasma mantle particles are observed in both hemispheres and the polar rain enhancement shows hemispheric asymmetry. The mixing of polar rain and plasma mantle may be occurred due to the movement of plasma mantle by electric field drift.