Heliospheric tomography using interplanetary scintillation observations: 2. Latitude and heliocentric distance dependence of solar wind structure at 0.1–1 AU
Heliospheric tomography using interplanetary scintillation observations: 2. Latitude and heliocentric distance dependence of solar wind structure at 0.1–1 AU
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DOI：
10.1029/97ja02162
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发表时间：
1998-02
影响因子：
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通讯作者：
M. Kojima;M. Tokumaru;H. Watanabe;A. Yokobe;K. Asai;B. Jackson;P. Hick
中科院分区：
文献类型：
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作者：
M. Kojima;M. Tokumaru;H. Watanabe;A. Yokobe;K. Asai;B. Jackson;P. Hick
行星际闪烁是在无法进行现场观测的地区测量太阳风的有用手段。然而，行星际闪烁测量涉及视线积分，它将视线沿线所有位置的贡献与实际观测联系起来。我们开发了计算机辅助断层扫描（CAT）程序来减少视线集成的不利影响。该计划利用太阳自转和太阳风运动来提供行星际闪烁观测可访问的空间中每个点的三维透视图，并优化三维太阳风速分布以适应观测结果。我们分析了日地环境实验室观测到的IPS速度，并证实：（1）太阳极小期的太阳风具有主导的极地高速太阳风区域，速度约为800 km s−1，在太阳赤道30°范围内，速度降至尤利西斯观测到的400 km s−1；（2）高速风的最终速度为750-900 km s−1，误差在0.1以内AU，因此，太阳风的加速度小于 0.1 AU。
Interplanetary scintillation is a useful means to measure the solar wind in regions inaccessible to in situ observation. However, interplanetary scintillation measurements involve a line-of-sight integration, which relates contributions from all locations along the line of sight to the actual observation. We have developed a computer assisted tomography (CAT) program to reduce the adverse effects of the line-of-sight integration. The program uses solar rotation and solar wind motion to provide three-dimensional perspective views of each point in space accessible to the interplanetary scintillation observations and optimizes a three-dimensional solar wind speed distribution to fit the observations. We analyzed IPS speeds observed at the Solar-Terrestrial Environment Laboratory and confirmed that (1) the solar wind during the solar minimum phase has a dominant polar high-speed solar wind region with speeds of about 800 km s−1 and within 30° of the solar equator speeds decrease to 400 km s−1 as observed by Ulysses, and (2) high-speed winds get their final speed of 750–900 km s−1 within 0.1 AU, and consequently, that acceleration of the solar wind is small above 0.1 AU.