Properties of the termination shock observed by Voyager 2
Properties of the termination shock observed by Voyager 2
复制标题
DOI：
10.1029/2008gl034869
复制
发表时间：
2008-10
影响因子：
5.2
通讯作者：
Hui Li;Chi Wang;J. Richardson
中科院分区：
文献类型：
--
作者：
Hui Li;Chi Wang;J. Richardson
2007年8月，航海者2号到达终止激波并进入距离约83.6天文单位的日鞘。由于激波锋面太阳风动压或波的变化，导致终端激波前后移动，航行者二号多次穿越终端激波。我们使用蒙特卡罗方法的最佳拟合解来定义上游和下游条件并确定终止激波的属性，例如激波法向、速度和强度。对于 DOY 243.819-243.875（激波 1）和 DOY 243.99-244.012（激波 2）上的交叉点，终端激波几乎沿径向移动。激波几乎垂直，激波法线与太阳风磁场之间的夹角约为70°。在第一次穿越时，终端激波以约 100 km s−1 的速度远离太阳，而在第二次穿越时，终端激波以约 30 km s−1 的速度向太阳移动。终止激波的密度比分别为2.2和1.6。对于这两个穿越事件，发现相对于终止激波下游的热离子而言，流动仍然是超音速的，这可能是由于大部分太阳风能转移到拾取离子的事实。
In August 2007, Voyager 2 reached the termination shock and entered the heliosheath at a distance of about 83.6 AU. Due to the variations of the solar wind dynamic pressure or waves on the shock front, the termination shock moved back and forth, and Voyager 2 crossed the termination shock multiple times. We use the best fit solution of the Monte‐Carlo method to define the upstream and downstream conditions and determine the properties of termination shock, such as the shock normal, speed, and strength. For the crossings on DOY 243.819‐243.875(shock 1) and DOY 243.99‐244.012(shock 2), the termination shock moved almost in the radial direction. The shock is nearly perpendicular, and the angle between the shock normal and the solar wind magnetic field is about 70°. In the case of the first crossing, the termination shock moved away from the Sun with a speed of about 100 km s−1, whereas the termination shock moved toward Sun with a speed of about 30 km s−1 for the second crossing. The density ratios of the termination shock are 2.2 and 1.6, respectively. For both crossing events, the flow is found to be still supersonic with respect to the thermal ions downstream of the termination shock, probably due to the fact that most of the solar wind energy is transferred to the pickup ions.