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地球弓激波是超音速太阳风和地球磁层相互作用的产物,以往由于数据所限,人们发展的模型仅考虑了近地情况,而对于远地弓激波的位型,以及其他因素例如行星际磁场B_y对弓激波位型的影响,人们还不是很清楚.通过统计分析ARTEMIS卫星2011年1月至2015年1月期间的弓激波穿越事件,首先拟合修正了Chao弓激波模型(最常用的弓激波模型之一)中尾部张角a表达式的系数,得到适用于中远地(月球轨道处,地心距离-20R_E>X>-50R_E)弓激波的模型系数,然后研究了行星际磁场B_y分量对弓激波尾部张角a的影响.结果表明:(1)拟合的模型系数相对于原系数来说,在中远地与观测结果更吻合;(2)弓激波尾部张角a随行星际磁场B_y分量的增大而增大,且正的B_y对张角的影响比B_y为负的情况影响更大.研究结果为进一步建立包含行星际磁场B_y分量的弓激波模型提供了参考.
The Earth’s bow shock is the product of the interaction between the supersonic solar wind and the Earth’s magnetosphere. In the past, due to limited data, people developed models that considered only the near-field conditions. For the type of far-away bow shock, and other factors such as the line It is not yet clear how the B_y of the interplanetary magnetic field impinges on the shape of the bow shock.By statistical analysis of the bow shock crossing events from January 2011 to January 2015 in ARTEMIS satellite, the Chao bow shock model (One of the most commonly used bow shock models), the model coefficients applicable to the bow shocks in COSCO (moon orbit, geocentric distance -20R_E> X> -50R_E) are obtained, and then The effect of the B_y component of the interplanetary magnetic field on the tail angle a of the bow shock was studied. The results show that: (1) The fitted model coefficients are more consistent with the observed results in COSCO than the original coefficients; (2) The angle a of aft tail increases with the increase of the B_y component of the interplanetary magnetic field, and the influence of positive B_y on the opening angle is more affected than the case of a negative B_y.Results In order to further establish the bow-excitation Wave model provides a reference.