报告题目：Kinetic Alfvén wave turbulence in the Earth’s cusp region 

　　报告人：王铁砚博士（北京航天航空大学） 

　　报告摘要：The Earth’s cusp region offers an ideal laboratory for studying turbulence in a parameter regime different from that of solar wind. Previous work has demonstrated the existence of Drift Kinetic Alfvén vortices in this region. In this work, we ask whether the strong turbulence in the cusp may still display qualitative properties that are similar to those of the linear waves. We investigate the dispersive properties of the linear modes to determine the nature of fluctuations. It is shown by using the k-filtering technique that the wave vector and dispersion relation of the turbulence are consistent with linear KAW solutions of the Maxwell-Vlasov equations. In addition, the ratio of the electric to magnetic field energy and magnetic field polarization (in the plane perpendicular to k) agree well with theoretical results of KAW mode. Therefore, the turbulence in the cusp region is demonstrated to have Kinetic Alfvén wave properties. Furthermore, we calculate the density gradient vector using multipoint measurements of plasma density and find that the density gradient  is nearly parallel to k, which suggest that the waves are much possibly generated through resonant mode conversion. 

　　报告时间：2016年10月20日（星期四）10:30-11:30 

　　报告地点：紫台办公大楼619会议室 

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