| タイトル | Can Kelvin-Helmholtz Instabilities of Jet-Like Structures and Plumes Cause Solar Wind Fluctuations at 1 AU? |
| 著者（英） | Suess, Steven T.; Shyamsundar, Parhi; Sulkanen, Martin E. |
| 著者所属（英） | NASA Marshall Space Flight Center |
| 発行日 | 1998-01-01
1998 |
| 言語 | eng |
| 内容記述 | The long high latitude sampling of Ulysses provides the opportunity to study fine structures. At latitudes poleward of approx. -60 deg, the solar wind had fluctuations in velocity gradients which were attributed to "microstreams". The data also suggested fluctuations characterized by magnetic plus thermal pressure balance structures ("PBS"). At higher frequencies, MHD turbulence was observed and found to be less evolved than in the ecliptic, but essentially independent of heliographic latitude. It is argued here that microstreams, PBS, and MHD turbulence could all be the remnants of mixing due to shear instabilities associated with plumes and other filamentarystructures ("jets") in coronal holes. To show this we simulate a plume-like jet in the presence of an ambient magnetic field. We find the presence of the ambient field reduces the growth rate of the instability, but the shear between a jet and its ambient still becomes unstable to the MHD Kelvin-Helmholtz ("KH") instability when the shear speed is larger than the largest local magnetosonic speed - a condition probably satisfied for plumes. |
| NASA分類 | Solar Physics |
| 権利 | No Copyright |
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