摘要： Here, we present a case study of THEMIS and ground‐based observations of the perturbed dayside magnetopause and the geomagnetic field in relation to the interaction of an interplanetary directional discontinuity (DD) with the magnetosphere on 16 June 2007. The interaction resulted in a large‐scale local magnetopause distortion of an “expansion – compression – expansion” (ECE) sequence that lasted for ∼15 min. The compression was caused by a very dense, cold, and fast high‐βmagnetosheath plasma flow, a so‐called plasma jet, whose kinetic energy was approximately three times higher than the energy of the incident solar wind. The plasma jet resulted in the effective penetration of magnetosheath plasma inside the magnetosphere. A strong distortion of the Chapman‐Ferraro current in the ECE sequence generated a tripolar magnetic pulse “decrease – peak– decrease” (DPD) that was observed at low and middle latitudes by some ground‐based magnetometers of the INTERMAGNET network. The characteristics of the ECE sequence and the spatial‐temporal dynamics of the DPD pulse were found to be very different from any reported patterns of DD interactions with the magnetosphere. The observed features only partially resembled structures such as FTE, hot flow anomalies, and transient density events. Thus, it is difficult to explain them in the context of existing models. Key Points A magnetosheath jet causes a strong distortion of the dayside magnetopause The jet results in intense plasma penetration inside the magnetosphere Ground magnetic variations trace the jet traveling along the magnetopause 其他題名： J. Geophys. Res 出版者： Washington, DC: Blackwell Publishing Ltd 出版日期： 2012-08 出處： Journal of Geophysical Research: Space Physics, 2012-08, Vol.117 (A8), p.n/a 資源來源： Wiley Online Library 版權： 2012. American Geophysical Union. All Rights Reserved. 版權： 2015 INIST-CNRS 版權： Copyright American Geophysical Union 2012 識別號： ISSN: 0148-0227 識別號： ISSN: 2169-9380 識別號： EISSN: 2156-2202 識別號： EISSN: 2169-9402 識別號： DOI: 10.1029/2011JA016861
