Basic research for space climate

中部大学的Hakamada用他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中的光球之间绘制了磁力线，并绘制了高分辨率的地图，从中我们可以识别出磁场的三维结构和大小。他为几乎两个太阳活动周期的201个卡灵顿旋转绘制了201张地图，并将它们汇编成电影，从中我们可以发现最大相位周围的磁极反转和最小相位周围的稳定的偶极子状磁场结构。利用磁力线的迹线，得到了同一磁力线两端的日冕磁场（Br_sou）和光球磁场（Br_pho）的径向分量。Hakamada在13次Carrington旋转的源面上构造了Br_sou和Br_pho的天气图。名古屋大学的Kojima在与磁场数据相同的13次旋转期间，用层析成像技术对行星际闪烁进行观测，绘制了源表面太阳风速度(V)的天气图。我们将这些数据分成两组，发现V、Br_sou和Br_pho之间的平面方程有如下良好的关系：(1) -1.5<log_<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的外部范围V=495.4+21.3log_<10>|Br_sou|-18.5log_<10>|Br_pho|。这一结果表明太阳风由两种风组成；即：(1)由400 km/s加速到900 km/s的与日冕场大小有关的机制的风；(2)不依赖于磁场，平均速度约为436 km/s的背景风。

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.