2002年10月Millstone Hill地区电离层暴时特性研究

磁暴期间电离层行为是电离层物理的重要研究内容.本文利用美国Millstone Hill非相干散射雷达以及GPS-TEC数据资料，分析了2002年10月13-17日和22-26日磁暴事件期间电离层电子密度响应在不同高度存在的差异.结果表明：正、负相暴电子密度的变化幅度随高度变化趋势相同，但不同高度上响应的时间、相位和幅度存在差异；负相暴最大变化幅度所在高度值同静时峰高值非常吻合，二者有很好的线性关系，但正相暴最大变化幅度所在高度值同静时峰高值无关，波动较大，意味着电离层正相暴响应更易到达各个高度上；特别地，22-26日负相暴在能量初次耦合进入电离层时高高度有极小的变化，其最大绝对变化量仅为低高度的4%.大气成分和风场的共同作用是两次负相暴发生的主要原因，但前者成分效应明显，后者动力学作用明显，有时甚至700 km以上电离层的贡献也是不可忽略的.

An investigation of responses to the October 2002 storms of the ionosphere at Millstone Hill

The ionospheric behavior during magnetic storms is an important research topic in ionospheric physics. In this paper, the ionospheric observations from the 31-days Millstone Hill incoherent scatter radar and GPS satellites are used to study the ionospheric responses of electron density at different altitudes during the magnetic storm events on October 13-17 and 22-26, 2002. The results show that the absolute changes in electron density versus the heights are the same for both positive and negative phase storms, however, time, phase and magnitude of responses are inconsistent with each other at different heights; The height of the maximum absolute change of the negative phase storm is highly consistent with the non-storm F₂ layer height, which has a good correlation between them, while the positive phase storm has no relation and fluctuation is larger. It means that the response of the positive phase storm arrives at all altitudes easier. Especially, the negative phase storm during 22-26 has a smaller change at higher heights when the energy is first coupled into the ionosphere, accounting for about 4% of the lower height, and the height of the maximum absolute change is uncertain. Though the composition is more obvious for the former and the wind field is more apparent for the latter, the combined contribution of atmospheric composition and wind field might be the main causes of the two negative phase storms, and sometimes even the contribution of the ionosphere above 700 km cannot be negligible.