Correlated observations linking loss of energetic protons to EMIC waves  

作　　者：YANG Chang WANG ZongQiang XIAO FuLiang HE ZhaoGuo XIE YanQiong ZHANG Sai HE YiHua LIU Si ZHOU QingHua 

机构地区：[1]School of Physics and Electronic Sciences,Changsha University of Science and Technology,Changsha 410114,China [2]Sate Key Laboratory of Space Weather,Chinese Academy of Sciences,Beijing 100190,China [3]Planetary Environmental and Astrobiological Research Laboratory(PEARL),School of Atmospheric Sciences,Sun Yat-sen University,Zhuhai 519082,China [4]College of Meteorology and Oceanography,National University of Defense Technology,Nanjing 211101,China

出　　处：《Science China(Technological Sciences)》2022年第1期131-138,共8页中国科学（技术科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.41774194,41974212 and 42074198);the Specialized Research Fund for State Key Laboratories。

摘　　要：Electromagnetic ion cyclotron(EMIC)emission is an efficient mechanism for scattering loss of energetic protons.Here,we report an event that provides both in-situ observation of energetic proton differential fluxes in the inner magnetosphere and precipitation of protons at ionospheric altitudes.During the 7-8 September 2015 geomagnetic storm the Van Allen Probes observed strong EMIC waves around L=5 and a distinct decrement in fluxes of tens of keV protons around pitch angles 0°-45°.Meanwhile,precipitating protons at ionospheric altitudes were found to significantly enhanced(by several orders of magnitude),measured by NOAA 18 and 19 when they magnetically linked to the Van Allen Probe-A.By solving the Fokker-Planck diffusion equation,we show that EMIC waves can efficiently produce loss of energetic protons within about 2 h in the pitch angle range of~0°-45°,comparable to the satellite observations.

关 键 词：wave-particle interaction EMIC waves energetic proton scattering loss 

分 类 号：O441.4[理学—电磁学]