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Basic research for space climate

空间气候基础研究

基本信息

批准号：
16540408
负责人：
HAKAMADA Kazuyuki
金额：
$ 2.05万
依托单位：
Chubu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16540408/
关键词：
Space Climate Heliosphere Solar wind acceleration Coronal magnetic field Photospheric magnetic field long term variations Interplanetary space 宇宙空間三次元構造宇宙天気予報宇宙気候学

项目摘要

Hakamada of Chubu University traced magnetic field lines, with the Radial-Field model for the coronal magnetic field devised by himself, between the source surface of 2.5 solar radii and the photosphere in the corona and drew high resolution maps from which we can identify both the three-dimensional structure and the magnitude of the field. He drew 201 maps for 201 Carrington rotations during almost two solar activity cycles and compiled them into a motion picture from which we can found the reversal of magnetic polarity around the maximum phase and the steady dipole like structure of the field around the minimum phase. We obtain the radial components of the coronal magnetic field (Br_sou) and the photospheric magnetic field (Br_pho) at both the ends of the same field line by the trace of field lines. Hakamada constructed synoptic maps for Br_sou and ones for Br_pho on the source surface for thirteen Carrington rotations. Kojima of Nagoya University drew the synoptic maps of the solar wind velocity (V) on the source surface estimated by the tomography technique with the observations of interplanetary scintillation during the same thirteen rotations as the magnetic data. We divided these data into two groups and found good relations of the equation of plane among V, Br_sou and Br_pho as follows ; (1)the group for -1.5<log_<10>|Br_sou|<0.0, and -1.0<log_<10>|Br_pho|<1.5, V=960.5+328.6log_<10>|Br_sou|-72.0log_<10>|Br_pho|, and (2)the group for the outside range of the group 1, V=495.4+21.3log_<10>|Br_sou|-18.5log_<10>|Br_pho|. This result suggests that the solar wind consists of two kinds of wind ; that is, (1)the wind that is accelerated from 400 km/s to 900 km/s by the mechanism related to the magnitude of the coronal field, and (2)the background wind that is independent of the magnetic fields and has the speed of about 436 km/s on the average.

日本中部大学的Hakamada利用自己设计的日冕磁场径向场模型，在2.5太阳半径的源表面和日冕光球之间追踪磁场线，并绘制了高分辨率地图，从中我们可以识别磁场的三维结构和大小。他在近两个太阳活动周期中绘制了201张卡林顿旋转的201张地图，并将它们汇编成一幅运动图像，从中我们可以发现最大相位周围的磁极性反转和最小相位周围的稳定偶极子状场结构。由磁力线迹线得到了同一磁力线两端的日冕磁场和光球磁场的径向分量。Hakamada为Br_sou和Br_pho在13次卡林顿旋转的源表面上构建了天气图。名古屋大学的Kojima利用行星际闪烁的观测结果绘制了源面上太阳风速度（V）的天气图，这些观测结果与磁测数据在13个自转周期内的观测结果相同，是通过层析成像技术估算的。我们将这些数据分成两组，发现V、Br_sou和Br_pho之间的平面方程关系良好：（1）-1.5 <10>|Br_sou| <0.0和-1.0<log_<10>|Br_pho| <1.5，V=960.5+328.6log_<10>|Br_sou|-72.0log_<10>|Br_pho|（2）组1的外区组，V=495.4+ 21.3log_1 <10>|Br_sou|-18.5log_<10>|Br_pho|.这一结果表明，太阳风由两种风组成：（1）通过与日冕场大小相关的机制从400 km/s加速到900 km/s的风，以及（2）与磁场无关的背景风，平均速度约为436 km/s。