Intermittent outflows at the edge of an active region - a possible   source of the solar wind?

doi:10.1051/0004-6361/200913712

CORC > 北京大学 > 地球与空间科学学院

	Intermittent outflows at the edge of an active region - a possible source of the solar wind?
	He, J.S. ; Marsch, E. ; Tu, C.Y. ; Guo, L.J. ; Tian, H.
刊名	astronomy astrophysics
	2010
关键词	solar wind Sun: photosphere Sun: chromosphere Sun: corona EUV IMAGING SPECTROMETER LONG-PERIOD OSCILLATIONS H-ALPHA SURGES X-RAY JETS CORONAL FUNNELS MAGNETIC RECONNECTION TRANSITION REGION PLASMA FLOWS POLAR PLUMES ORIGIN
DOI	10.1051/0004-6361/200913712
英文摘要	Context. It has already been established that the solar wind may originate at the edges of active regions (ARs), but the key questions of how frequently these outflows occur, and at which height the nascent solar wind originates have not yet been addressed. Aims. We study the occurrence rate of these intermittent outflows, the related plasma activities beneath in the low solar atmosphere, and the interplanetary counterparts of the nascent solar wind outflow. Methods. We use the observations from XRT/Hinode and TRACE to study the outflow patterns. The occurrence frequency of the intermittent outflow is estimated by counting the occurrences of propagating intensity enhancements in height-time diagrams. We adopt observations of SOT/Hinode and EIS/Hinode to investigate the phenomena in the chromosphere associated with the coronal outflows. The ACE plasma and field in-situ measurements near Earth are used to study the interplanetary manifestations. Results. We find that in one elongated coronal emission structure, referred to as strand, the plasma flows outward intermittently, about every 20 min. The flow speed sometimes exceeds 200 km s(-1), which is indicative of rapid acceleration, and thus exceeds the coronal sound speed at low altitudes. The inferred flow speed of the soft-X-ray-emitting plasma component seems a little higher than that of the Fe IX/X-emitting plasma component. Chromospheric jets are found to occur at the root of the strand. Upflows in the chromosphere are also confirmed by blue-shifts of the He II line. The heliospheric plasma counterpart close to the Earth is found to be an intermediate-speed solar wind stream. The AR edge may also deliver some plasmas to a fraction of the fast solar wind stream, most of which emanate from the neighboring CH. Conclusions. The possible origin of the nascent solar wind in the chromosphere, the observed excessive outflow speed of over 200 km s(-1) in the lower corona, and the corresponding intermediate-speed solar wind stream in interplanetary space are all linked in our case study. These phenomena from the low solar atmosphere to the heliosphere near Earth in combination shed new light on the solar wind formation process. These observational results will constrain future modeling of the solar winds originating close to an AR.; Astronomy & Astrophysics; SCI(E); EI; 20; 1; 516
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/395746]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	He, J.S.,Marsch, E.,Tu, C.Y.,et al. Intermittent outflows at the edge of an active region - a possible source of the solar wind?[J]. astronomy astrophysics,2010.
APA	He, J.S.,Marsch, E.,Tu, C.Y.,Guo, L.J.,&Tian, H..(2010).Intermittent outflows at the edge of an active region - a possible source of the solar wind?.astronomy astrophysics.
MLA	He, J.S.,et al."Intermittent outflows at the edge of an active region - a possible source of the solar wind?".astronomy astrophysics (2010).