A sample of isolated Earth-impacting interplanetary coronal mass ejections (ICMEs) that occurred in the period January 2008 to August 2014 is analyzed to study in detail the ICME in situ signatures, with respect to the type of filament eruption related to the corresponding CME. Observations from different vantage points provided by the Solar and Heliospheric Observatory (SOHO) and the Solar Terrestrial Relations Observatory Ahead and Behind (STEREO-A and B) are used to determine whether each CME under study is Earth directed or not. For Earth-directed CMEs, a kinematical study was performed using the STEREO-A and B COR1 and COR2 coronagraphs and the Heliospheric Imagers (HI1), to estimate the CME arrival time at 1 AU and to link the CMEs with the corresponding in situ solar wind counterparts. Based on the extrapolated CME kinematics, we identified interacting CMEs, which were excluded from further analysis. Applying this approach, a set of 31 isolated Earth-impacting CMEs was unambiguously identified and related to the in situ measurements recorded by the Wind spacecraft. We classified the events into subsets with respect to the CME source location, as well as with respect to the type of the associated filament eruption. Hence, the events are divided into three subsamples: active region (AR) CMEs, disappearing filament (DSF) CMEs, and stealthy CMEs. The related three groups of ICMEs were further divided into two subsets: magnetic obstacle (MO) events (out of which four were stealthy), covering ICMEs that at least partly showed characteristics of flux ropes, and ejecta (EJ) events, not showing such characteristics. In this way, 14 MO-ICMEs and 17 EJ-ICMES were identified. The solar source regions of the non-stealthy MO-ICMEs are found to be located predominantly (9/10, 90%) within ± 30 ∘ $\pm30^{\circ}$ from the solar central meridian, whereas EJ-ICMEs originate predominantly (16/17, 94%) from source regions that are outside ± 30 ∘ $\pm30^{\circ}$ . In the next step, MO-events were analyzed in more detail, considering the magnetic field strength and the plasma characteristics in three different segments, defined as the turbulent sheath (TS), the frontal region (FR), and the MO itself. The analysis revealed various well-defined correlations for AR, DSF, and stealthy ICMEs, which we interpreted considering basic physical concepts. Our results support the hypothesis that ICMEs show different signatures depending on the in situ spacecraft trajectory, in terms of apex versus flank hits.

中文翻译：

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2008 年至 2014 年期间孤立地球影响行星际日冕物质抛射的太阳对地观测和特征

分析了 2008 年 1 月至 2014 年 8 月期间发生的孤立地球撞击行星际日冕物质抛射 (ICME) 样本，以详细研究 ICME 原位特征，以及与相应 CME 相关的细丝喷发类型。太阳和日光层天文台 (SOHO) 和前方和后方的太阳地球关系观测站 (STEREO-A 和 B) 提供的不同有利位置的观测用于确定所研究的每个 CME 是否指向地球。对于指向地球的 CME，使用 STEREO-A 和 B COR1 和 COR2 日冕仪以及日光层成像仪 (HI1) 进行了一项运动学研究，以估计 CME 到达 1 天文单位的时间并将 CME 与相应的原位太阳风同行。基于外推的 CME 运动学，我们确定了相互作用的 CME，这些 CME 被排除在进一步分析之外。应用这种方法，一组 31 个独立的影响地球的 CME 被明确识别并与 Wind 航天器记录的原位测量相关。我们根据 CME 源位置以及相关的细丝喷发类型将事件分为子集。因此，事件被分为三个子样本：活动区 (AR) CME、消失的细丝 (DSF) CME 和隐形 CME。相关的三组 ICME 进一步分为两个子集：磁障碍 (MO) 事件（其中四个是隐身的），涵盖至少部分显示出磁通绳特征的 ICME 和喷射物 (EJ) 事件，不显示此类特征。通过这种方式，确定了 14 个 MO-ICME 和 17 个 EJ-ICME。发现非隐身 MO-ICME 的太阳能源区域主要位于 (9/10, 90%) 距太阳中央子午线 ± 30 ∘ $\pm30^{\circ}$ 内，而 EJ-ICME 起源于主要 (16/17, 94%) 来自 ± 30 ∘ $\pm30^{\circ}$ 之外的源区域。在下一步中，更详细地分析 MO 事件，考虑三个不同部分的磁场强度和等离子体特性，定义为湍流鞘 (TS)、额区 (FR) 和 MO 本身。分析揭示了 AR、DSF 和隐形 ICME 的各种明确定义的相关性，我们在考虑基本物理概念的情况下对其进行了解释。我们的结果支持这样一个假设，即 ICME 根据原位航天器轨迹显示不同的特征，就顶点与侧翼命中而言。