Non-Spiral Interplanetary Magnetic Field and Coronal Mass Ejections

非螺旋行星际磁场和日冕物质抛射

基本信息

批准号：
14540416
负责人：
NAKAGAWA Tomoko
金额：
$ 1.02万
依托单位：
Tohoku Intsitute 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：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540416/
关键词：
CME acceleration of solar wind solar wind plasma IMF interplanetary space non-spiral field NOZOMI SOHO LASCO 「SOHO」衛星太陽風惑星空間磁場 ICME 太陽風の加速平面状磁場構造宇宙天気予報

项目摘要

The speeds of propagation of CMEs in interplanetary space are less distributed than their initial speeds measured on their departure from the limb of the Sun. Gopalswamy et al.(2000, 2001) presented a linear relationship between initial speeds of limb CMEs and their average acceleration during their travel time in interplanetary space. The linear relationship suggests that some dragging force is acting on CMEs. If similar relationship holds within 20 solar radii from the Sun, it would give information on the initial speed of 'ambient' solar wind in the vicinity of the Sun. The relationship between the initial acceleration and the initial speeds of limb CMEs was examined by using SOHO/LASCO CME Catalogue. For the cases for which correlation coefficient was fairly good (from -0.6 to -I), the 'ambient' solar wind speed within 20 solar radii was estimated to be 150 -570 km/s. It is somewhat slower than but close to the speeds of real solar wind measured in interplanetary space.Interplanetary counterparts of a halo CME which occurred on April 13, 1999, were observed by NOZOMI and ACE on April 16-18, when the two spacecraft were within 3 degrees in heliocentric longitude and 0.2 AU in heliocentric distance. The interplanetary magnetic fields had filamentary structures with large Bz components, and the Bz component was positive at NOZOMI while negative at ACE. Both magnetic fields were different from a magnetic cloud. It implies that the CME had a number of filamentary structures of magetic field lines with various directions. An interplanetary magnetic field of this kind can be used for detection of candidates of interplanetary counterparts of CMEs.

日冕物质抛射在行星际空间中的传播速度比它们离开太阳边缘时测得的初始速度分布更小。 Gopalswamy 等人（2000，2001）提出了肢体日冕物质抛射的初始速度与其在行星际空间中行进期间的平均加速度之间的线性关系。线性关系表明日冕物质抛射受到了一定的阻力。如果类似的关系在距太阳 20 个太阳半径范围内成立，它将提供有关太阳附近“环境”太阳风初始速度的信息。利用 SOHO/LASCO CME 目录检查了肢体 CME 的初始加速度和初始速度之间的关系。对于相关系数相当好的情况（从-0.6到-I），20个太阳半径内的“环境”太阳风速估计为150 -570 km/s。它比在行星际空间中测量到的真实太阳风速度稍慢，但接近于真实太阳风的速度。NOZOMI 和 ACE 在 4 月 16 日至 18 日观测到了 1999 年 4 月 13 日发生的光环 CME 的行星际对应物，当时两艘航天器在日心经度误差在 3 度以内，日心距离误差在 0.2 天文单位以内。行星际磁场呈丝状结构，Bz 分量较大，NOZOMI 处 Bz 分量为正，ACE 处 Bz 分量为负。这两个磁场都不同于磁云。这意味着日冕物质抛射具有许多不同方向的磁力线丝状结构。这种行星际磁场可用于探测日冕物质抛射的行星际对应物的候选者。