科研之友
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摘要
Whistler mode chorus waves are considered to play a central role in accelerating and scattering electrons in the outer radiation belt. While in situ measurements are usually limited to the trajectories of a small number of satellites, rigorous theoretical modeling requires a global distribution of chorus wave characteristics. In the present work, by using a large database of chorus wave observations made on the Time History of Events and Macroscale Interactions during Substorms satellites for about 5years, we develop prediction models for a global distribution of chorus amplitudes. The development is based on two main components: (a) the temporal dependence of average chorus amplitudes determined by correlating with the preceding solar wind and geomagnetic conditions as represented by the interplanetary magnetic field (IMF) B-z and AE index and (b) the determination of spatial distribution pattern of chorus amplitudes, specifically, the profiles in L in all 2h magnetic local time zones, which are categorized by activity levels of either the IMF B-z or AE index. Two separate models are developed: one based only on the IMF B-z and the other based only on AE. Both models predict chorus amplitudes for two different latitudinal zones separately: |magnetic latitude (MLAT)|<10 degrees, and |MLAT|=10 degrees-25 degrees. The model performance is measured by the coefficient of determination R-2 and the rank-order correlation coefficient (ROCC) between the observations and model prediction results. When tested for a new data interval of similar to 1.5years, the AE-based model works slightly better than the IMF B-z-based model: for the AE-based model, the mean R-2 and ROCC values are similar to 0.46 and similar to 0.78 for |MLAT|<10 degrees, respectively, and similar to 0.4 and similar to 0.74 for |MLAT|=10 degrees-25 degrees, respectively; for the IMF B-z-based model, the mean R-2 and ROCC values are similar to 0.39 and similar to 0.74 for |MLAT|<10 degrees, respectively, and similar to 0.33 and similar to 0.70 for |MLAT|=10 degrees-25 degrees, respectively. We provide all of the model information in the text and supporting information so that the developed chorus models can be used for the existing outer radiation belt electron models.
- 出版日期2015-4
