We study the interaction of three solar wind (SW) structures, two stream interaction regions, and one interplanetary coronal mass ejection, with Mars’ plasma environment during November 20–27, 2007. This period corresponds to the solar minimum between the solar cycles 23 and 24 which was characterized by very low values of the SW density and dynamic pressure and low interplanetary magnetic field magnitude. During that time the Mars Express orbit was in the terminator plane, while the Earth, Sun, and Mars were almost aligned, so we use the Advance Composition Explorer and Solar Terrestrial Relations Observatory probes as SW monitors in order to identify and characterize the structures that later hit Mars. We find that the passage of these structures caused strong variations in the bow shock location (between 2.2 and 3.0 R_M), compression of the magnetospheric cavity (up to 45%), and an increased transterminator flow below 2 R_M (by a factor of ≤ 8). This study shows that during times of low solar activity, modest space weather phenomena may cause large variations of plasma flow at Mars.

中文翻译：

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太阳最低23/24期间空间天气现象与火星等离子体环境的相互作用

我们研究了三个太阳风（SW）结构，两个流相互作用区域和一个行星际日冕物质抛射与火星的等离子环境在2007年11月20-27日之间的相互作用。该时间段对应于太阳周期之间的太阳最小值23和24的特征在于SW密度和动态压力的值非常低，而行星际磁场强度很低。在此期间，火星快车轨道位于终结器平面内，而地球，太阳和火星几乎都对准了，因此我们使用Advance Composition Explorer和Solar Terrestrial Relations Observatory探测器作为SW监视器，以识别和表征那些后来打火星。我们发现这些结构的通过导致了弓形冲击位置的强烈变化（介于2.2和3.0 R _M之间），磁层空腔的压缩（高达45％），以及在2 R _M以下（以≤8的因数）增加的终止子流量。这项研究表明，在低太阳活动时期，适度的太空天气现象可能会导致火星的等离子体流量发生较大变化。