Latest progress on interactions between VLF/ELF waves and energetic electrons in the inner magnetosphere     

XIAO FuLiang    ZONG QiuGang  SU ZhenPeng  TIAN Tian & ZHENG HuiNan School of Physics  Electronic Sciences  Changsha University of Science  Technology  Changsha  China  State Key Laboratory of Space Weather  Chinese Academy of Sciences  Beijing 《中国科学:地球科学(英文版)》2010,(3)

Interactions between very/extremely low frequency (VLF/ELF) waves and energetic electrons play a fundamental role in dynamics occurring in the inner magnetosphere. Here, we briefly discuss global properties of VLF/ELF waves, along with the variability of the electron radiation belts associated with wave-particle interactions and radial diffusion. We provide cases of electron loss and acceleration as a result of wave-particle interactions primarily due to such waves, and particularly some preliminary results...  相似文献   

Integration of surface geophysical methods for fracture detection in crystalline bedrocks of southwestern Nigeria     

A. A. Adepelumi  M. -J. Yi  J. -H. Kim  B. D. Ako  J. S. Son 《Hydrogeology Journal》2006,14(7):1284-1306

The application of electrical imaging and very low frequency (VLF) electromagnetics was investigated for the purpose of delineating basement fracture zones, and to show how incorporating a priori information in numerical modelling would facilitate the location of fractured zones within a basement rock more precisely. To this end, direct current (DC) dipole–dipole resistivity and VLF modelling and inversion experiments were carried out to evaluate the efficacy of the methods in detecting low-resistivity fracture zones in a typical crystalline basement rock that is favourable for groundwater accumulation. Most wells drilled in such an environment usually have low yields. Results of the numerical experiment generally indicate that fractures covered by moderate overburden, and having considerable depth, extent, and thickness compared to the depth of fracture burial, produce good responses resulting in high-resolution resistivity images. Lower resolution resistivity images were obtained as the thickness of the overburden increased. Also, the model investigations indicate that width of the fracture zone plays a major role in controlling image resolution. Conclusions from the synthetic modelling were confirmed by resistivity and VLF data gathered across a suspected fault in a hard rock terrain of southwestern Nigeria. The results from the field data are in general agreement with the numerical modelling experiments.Integración de métodos geofísicos superficiales para la detección de fracturas en macizos rocosos cristalinos del suroeste de Nigeria.  相似文献