Response of the midtail electric field to enhanced solar wind energy input
Response of the midtail electric field to enhanced solar wind energy input
复制标题
中尾电场对增强太阳风能输入的响应
DOI：
10.1029/1999ja900166
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发表时间：
1999
影响因子：
--
通讯作者：
O. Troshichev
中科院分区：
文献类型：
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作者：
R. Nakamura;L. Bargatze;T. Mukai;T. Nagai;K. Baker;M. Hairston;P. Reiff;A. Petrukovich;M. Nozdrachev;O. Troshichev
我们研究了1995年11月22日两个亚暴间隔的中尾等离子体和场参数对增强的太阳风电场输入的响应。这两个亚暴的太阳风输入特征是完全不同的，它们在1108和1502 UT有主要的Pi2爆发。1108 UT亚暴的太阳风输入有一个短时间尺度（约0.5小时）的电场增强高达1.5 mV/m，而1502 UT亚暴的太阳风电场连续超过1.5 mV/m约0.2小时。与两个亚暴的膨胀阶段的开始，电场波动的中尾等离子体片开始。电场扰动持续的时间间隔接近时间的长度，在此期间，太阳风电场增强。中尾等离子体片电场对增强的太阳风输入有45 - 80分钟的时间延迟。压力下降，开始于两个亚暴的开始，结束于这两个亚暴完全不同：在1108 UT亚暴过程中，压力下降直到接近平静时间水平，而在1502 UT亚暴的扩张阶段，压力下降到平静时间水平以下，并保持在这个低水平，直到恢复阶段的后期。利用极冠电位降和中尾压力剖面，我们估计了昼侧和夜侧电位降之间的关系。我们认为，夜侧通量输送率的差异可以控制中尾的配置，可以解释为什么尾压响应不同的两个亚暴的扩张和恢复阶段。
We study the response of midtail plasma and field parameters to enhanced solar wind electric field input for two substorm intervals on November 22, 1995. The solar wind input signatures were quite different for these two substorms, which had major Pi2 onsets at 1108 and 1502 UT. The solar wind input for the 1108 UT substorm had a short timescale (∼0.5 hour) electric field enhancement up to 1.5 mV/m, whereas the solar wind electric field for the 1502 UT substorm continuously exceeded 1.5 mV/m for ∼2 hours. In association with the expansion phase onsets of both substorms, the electric field fluctuation in the midtail plasma sheet commenced. The electric field disturbances lasted for a time interval close to the length of time, in which the solar wind electric field was enhanced. The midtail plasma sheet electric field responded well to the enhanced solar wind input with a time delay of 45–80 min. The pressure decrease, which started at the onset of both substorms, ended quite differently for these two substorms: the pressure decreased until it approached the quiet time level in the course of the 1108 UT substorm, whereas the pressure dropped below the quiet time level during the expansion phase of the 1502 UT substorm and stayed at this low level until late in the recovery phase. Using polar cap potential drop and the pressure profile in the midtail, we estimate the relationship between the dayside and nightside potential drop. We suggest that the difference in the nightside flux transport rate could control the configuration of the midtail and could explain why the tail pressure responded differently during the expansion and recovery phase of the two substorms.