Interplanetary Planar Magnetic Structures

行星际平面磁结构

基本信息

批准号：
07640591
负责人：
NAKAGAWA Tomoko
金额：
$ 0.9万
依托单位：
Tohoku Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07640591/
关键词：
planar magnetic structures interplanetary magnetic field interplanetary space active region expansions sakigake Yohkoh solar wind soft X-ray image

项目摘要

Planar magnetic structures in which interplanetary magnetic field vector takes almost all directions that are parallel to a plane are correlated with EXPANDING ACTIVE REGIONS on the Sun by using Sakigake solar wind data and Yohkoh soft X-ray images of the Sun. During the period from January to July, 1993, we could identify three typical planar magnetic structures with the active region expansions found by Uchida et al. [1992] in the Yohkoh soft X-ray images, from which loop-like structures of active-region corona expand outward repeatedly at speeds of a few to a few tens of km/s even in the absence of any sizable flares. The active region expansions are expected to play an important role in mass loss from the Sun. On the other hand, not all the active regions were observed as planar structures in interplanetary space. In 16 Sakigake observations of solar wind plasma whose solar sources coincided with active regions, 9 had non-spiral magnetic field including planar structures, high ion density or both of them, but the other 7 (44%) exhibited no significant difference from average solar wind with spiral field.Pressure gradient in the solar wind is examined as a candidate cause of planar magnetic structures. In five of Sakigake planar magnetic structures with no bulk-speed gradient, two were in the regions of pressure gradient but the others were not. Flattened, intertwined flux tubes of high-beta plasma (Crooker et al., 1996) are re-examined to model planar magnetic structures. In order to reproduce a planar magnetic structure, a large number of flux ropes with small helicity are required. Variation of field direction is mainly due to variation of orientation of rope axs, rather than to field rotations in each of ropes.

平面磁性结构通过使用Sakigake太阳风数据和太阳的Yohkoh Soft X射线图像，在星际磁场矢量几乎采用平行于平面的所有方向都与太阳上的活动区域相关。在1993年1月至7月期间，我们可以确定三个典型的平面磁性结构，并具有Uchida等人发现的活动区域扩展。 [1992]在Yohkoh软X射线图像中，即使在没有任何可观的耀斑的情况下，活动区电晕的循环样结构也以少数至几十km/s的速度反复向外扩展。预计主动区域的扩展将在太阳的质量损失中起重要作用。另一方面，并非所有活性区域都被视为行星际空间中的平面结构。在太阳能源与活动区域相吻合的太阳风等离子体的16个sakigake观察中，有9个具有非螺旋磁场，包括平面结构，高离子密度或两者，但其他7（44％）与平均太阳能无显着差异带有螺旋场的风。太阳风中的压力梯度被研究为平面磁性结构的候选原因。在没有散装速度梯度的五个Sakigake平面磁性结构中，有两个在压力梯度的区域，而其他则没有。将高β等离子体的扁平，交织的通量管（Crooker等，1996）重新检查以建模平面磁性结构。为了重现平面磁性结构，需要大量具有较小螺旋的通量绳。场方向的变化主要是由于绳轴方向的变化，而不是每个绳索中的场旋转。