[P-EM05] Cosmophysical plasma jets

[PEM05-P03] Origin of large-scale plasma jets in the magnetosheath

*ALEXEI DMITRIEV¹ (1.Institute of Space Science, National Central University, Jungli City, Taiwan)

キーワード：solar wind, bow shock, magnetosheath, plasma jets

Previous studies shown that an important source of the solar wind plasma inside the dayside magnetosphere is large-scale plasma jets, fast and dense plasma streams in the magnetosheath. A number of mechanisms have been proposed for the jet generation and are used for interpretation of experimental data. THEMIS observations of plasma and magnetic field in the magnetosheath provided a lot of new information about plasma jets. Statistically, it has been shown that the duration of jets peaks at ~30 second and they are predominantly observed during intervals of quasi-radial IMF. It is believed that most of jets are formed at rippled quasi-parallel bow shock. However, this mechanism is difficult to apply for generation of large-scale jets of minute duration. We studied large-scale plasma jets, whose duration varies from 30 sec to 3 minutes. From THEMIS observations, it was collected 642 large-scale jets in the years 2007 – 2009. Analysis of those jets with using upstream solar wind conditions has shown that the jets generated under quasi-radial IMF are usually slower and weaker. Fastest and strongest jets are generated in interaction of the bow shock with rotational discontinuities.