Estimating the solar wind pressure at comet 67P from Rosetta magnetic field measurements
Estimating the solar wind pressure at comet 67P from Rosetta magnetic field measurements
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根据 Rosetta 磁场测量估算 67P 彗星的太阳风压力
DOI：
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发表时间：
2019
影响因子：
3.3
通讯作者：
H. Madanian
中科院分区：
文献类型：
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作者：
A. Timár;Z. Németh;K. Szego;M. Dósa;A. Opitz;H. Madanian
目的：太阳风压是空间天气的一个重要参数，在太阳风与行星等离子体环境的相互作用中起着至关重要的作用。在这里，我们研究了从Rosetta磁场数据中确定太阳风压代理的可能性，该数据在67P/Churyumov-Gerasimenko彗星的感应磁层深处测量。这个压力代理不仅对其他与Rosetta有关的研究有用，而且还可以作为一个新的、独立的输入数据库，用于空间天气传播到太阳系的其他位置。
方法：对于彗星感应磁层，用太阳风动压平衡堆积区最里面的磁压。最近对Rosetta数据的研究表明，堆积区的最大磁场可以通过在彗星磁层内部区域进行磁场测量来近似，该区域靠近反磁腔的边界，由此可以估计外部太阳风压力。
结果：我们能够确定2015年4月下旬至2016年1月期间罗塞塔航天器位于反磁腔边界附近的时间间隔的太阳风压力指标。然后，我们将我们的Rosetta压力代理与从近地推算到彗星67P的太阳风压进行了比较。在排除暂态事件引起的扰动后，我们发现两个数据集之间存在很强的相关性。
Aims: The solar wind pressure is an important parameter of space weather, which plays a crucial role in the interaction of the solar wind with the planetary plasma environment. Here we investigate the possibility of determining a solar wind pressure proxy from Rosetta magnetic field data, measured deep inside the induced magnetosphere of comet 67P/Churyumov-Gerasimenko. This pressure proxy would be useful not only for other Rosetta related studies but could also serve as a new, independent input database for space weather propagation to other locations in the Solar System.
Method: For the induced magnetospheres of comets the magnetic pressure in the innermost part of the pile-up region is balanced by the solar wind dynamic pressure. Recent investigations of Rosetta data have revealed that the maximum magnetic field in the pile-up region can be approximated by magnetic field measurements performed in the inner regions of the cometary magnetosphere, close to the boundary of the diamagnetic cavity, from which the external solar wind pressure can be estimated.
Results: We were able to determine a solar wind pressure proxy for the time interval when the Rosetta spacecraft was located near the diamagnetic cavity boundary, between late April 2015 and January 2016. We then compared our Rosetta pressure proxy to solar wind pressure extrapolated to comet 67P from near-Earth. After the exclusion of disturbances caused by transient events, we found a strong correlation between the two datasets.