Electron drift echoes induced by negative solar wind dynamic pressure pulses
<div> <div> <div> <p>Sudden dropouts of the relativistic electron fluxes with drift echoes are closely related to a&#160;positive solar wind dynamic pressure pulse, such as an interplanetary shock impact on the&#160;magnetosphere. In this study, we further examine how magnetospheric energetic particles&#160;response to a negative solar wind dynamic pressure pulse on the 11th May 2017. During&#160;this event, sudden dropouts of energetic electron fluxes with an energy of 200 keV&#8764;750&#160;keV and enhancements of the relativistic electron fluxes of 0.85 MeV&#8764;2.7 MeV were observed simultaneously by both Van Allen Probes. The periodic electron flux dropout-recovery or enhancement-decay signatures, which are attributed to electron drift behaviors,&#160;exhibited energy dependence. Based on the electron phase space density profile and the&#160;induced electric field variation, we interpreted this phenomenon as the consequence of radially outward transportationss of electrons caused by the electric field impulse induced by the&#160;negative dynamic pressure pulse.</p> </div> </div> </div>