Two-station interplanetary scintillation measurements of solar wind speed near the Sun using the X-band radio signal of Nozomi spacecraft
Two-station interplanetary scintillation measurements of solar wind speed near the Sun using the X-band radio signal of Nozomi spacecraft
复制标题
使用Nozomi航天器的X波段无线电信号对太阳附近的太阳风速进行两站行星际闪烁测量
DOI：
10.1007/s11207-011-9864-9
复制
发表时间：
2012
期刊：
影响因子：
2.8
通讯作者：
and M. Kojima
中科院分区：
文献类型：
--
作者：
Tokumaru;M.;S. Fujimaki;M. Higashiyama;A. Yokobe;T. Ohmi;K. Fujiki;and M. Kojima
在2000 - 2001年Nozomispacecraft的太阳会合期间，利用X波段无线电信号，对13至37 RS距离范围内的太阳风速度进行了行星际闪烁（IPS）测量。在这项研究中采用了两个大口径天线，两个天线之间的基线是几倍于菲涅耳尺度的X波段。我们成功地检测到了IPS的正相关性从接收到的信号数据的互相关分析在入口，并估计太阳风的速度从时间滞后对应的最大相关性假设太阳风径向流动。估计的速度范围在200到540 km s-1之间，大多数低于400 km s-1。我们研究了径向变化的太阳风速度沿着相同的流线通过比较的Nozomi数据在更大的距离获得的数据。在这里，我们使用的太阳风速度数据从327兆赫IPS观测的太阳-地球环境实验室（STEL），名古屋大学，并在现场测量的高级成分探测器（ACE）的比较，我们认为的视线整合固有的IPS观测的比较效果。因此，Nozomispeed数据被证明属于太阳风的慢速部分。30 RS内的速度估计被发现系统地比终端速度慢10 - 15%，这表明缓慢的太阳风在13和30 RS之间加速。
Interplanetary scintillation (IPS) measurements of the solar wind speed for the distance range between 13 and 37RSwere carried out during the solar conjunction of theNozomispacecraft in 2000 – 2001 using the X-band radio signal. Two large-aperture antennas were employed in this study, and the baseline between the two antennas was several times longer than the Fresnel scale for the X-band. We successfully detected a positive correlation of IPS from the cross-correlation analysis of received signal data during ingress, and estimated the solar wind speed from the time lag corresponding to the maximum correlation by assuming that the solar wind flows radially. The speed estimates range between 200 and 540 km s−1with the majority below 400 km s−1. We examined the radial variation in the solar wind speed along the same streamline by comparing theNozomidata with data obtained at larger distances. Here, we used solar wind speed data taken from 327 MHz IPS observations of the Solar-Terrestrial Environment Laboratory (STEL), Nagoya University, andin situmeasurements by theAdvanced Composition Explorer(ACE) for the comparison, and we considered the effect of the line-of-sight integration inherent to IPS observations for the comparison. As a result,Nozomispeed data were proven to belong to the slow component of the solar wind. Speed estimates within 30RSwere found to be systematically slower by 10 – 15 % than the terminal speeds, suggesting that the slow solar wind is accelerated between 13 and 30RS.