Observation of Small-amplitude Electromagnetic Cyclotron Waves in the Solar Wind  

作　　者：Hai-Feng Yang Guo-Qing Zhao Heng-Qiang Feng Gilbert Pi Qiang Liu Liang Xiang Qiu-Huan Li Dan-Yang Ren 

机构地区：[1]Institute of Space Physics,Luoyang Normal University,Luoyang 471934,China [2]Henan Key Laboratory of Electromagnetic Transformation and Detection,Luoyang 471934,China [3]Faculty of Mathematics and Physics,Charles University,Prague 12116,Czech Republic

出　　处：《Research in Astronomy and Astrophysics》2023年第4期94-102,共9页天文和天体物理学研究（英文版）

基　　金：supported by NSFC under grant Nos.42174202,41874204,41974197,and 12103018;supported partly by the Excellent Young Scientists Fund in Henan Province under grant No.222300420061。

摘　　要：Our previous studies on low-frequency electromagnetic cyclotron waves(ECWs)with amplitudes larger than 0.1nT in the solar wind revealed that the left-handed(LH)polarized ECWs are the dominant waves,and these waves preferentially occur in plasma conditions of high proton speed(V_(p)),high proton temperature(T_(p)),low proton density(N_(p)).In the present study,using magnetic field and plasma data from the Wind mission between 2005 and2015,we perform a survey of small-amplitude ECWs with amplitudes smaller than 0.1 nT.It is revealed for the first time that the small-amplitude right-handed(RH)polarized ECWs tend to frequently occur in plasmas characterized by low V_(p),low T_(p),low N_(p),although the small-amplitude LH ECWs still preferentially occur in plasma conditions similar to the LH ECWs with amplitudes larger than 0.1 nT.Further investigation shows that the occurrences of small-amplitude RH ECWs and long-lasting radial interplanetary magnetic field(lrIMF)share the similar preferential plasma conditions of low T_(p)and low N_(p).During lrIMF events,in particular,the occurrence rates of RH and LH ECWs are comparable,with the occurrence rate of small-amplitude RH ECWs slightly larger than that of small-amplitude LH ECWs.The generation mechanism of the small-amplitude ECWs is discussed.

关 键 词：(Sun:)solar wind-magnetic fields-waves 

分 类 号：P182[天文地球—天文学] P353.8