AI 中文总结
本研究通过多点观测和多方位分析，证实磁云状抛射物可源于两个紧密CME的相互作用，并揭示其热力学演化特征。
AI 中文摘要
利用太阳轨道器、STEREO-A和Wind的就地观测，我们研究了行星际日冕物质抛射（ICME）的日球层演化。磁抛射物（ME）显示出磁云状（MCL）结构：前部区域磁场旋转且强度下降，随后是弱旋转的“后部区域”，磁场强度几乎恒定。近太阳极紫外和白光观测揭示，两个快速CME在短时间内接连发射并在低日冕高度相互作用，直接证明了MCL抛射物可以源于两个紧密间隔的CME在其顶点附近采样时的相互作用。利用近径向排列的太阳轨道器和STEREO-A观测，我们发现鞘层比ME膨胀得更快，这与“扫雪机”效应一致，而ME的性质大致遵循先前ICME研究中报道的趋势。STEREO-A和Wind观测（经度仅相差9.2度）的比较揭示了鞘层和ME内部可测量的中尺度变异性。我们在两个子结构中识别出双重多方行为，这与两个相互作用的CME合并形成观测到的MCL抛射物一致。ME中的这种双重行为在内日球层最为明显，并随日心距离增加而减弱，表明在径向膨胀过程中发生热力学均匀化，而鞘层从内日球层到1天文单位保持热力学对比。我们的发现表明，多方诊断有助于揭示与相互作用CME相关的热力学上不同的等离子体种群，为MCL抛射物中CME-CME相互作用提供额外证据，而传统的就地特征未显示此类相互作用的明确证据。
英文摘要
Using in-situ observations from Solar Orbiter, STEREO-A, and Wind, we investigate the heliospheric evolution of an interplanetary coronal mass ejection (ICME). The magnetic ejecta (ME) shows a magnetic-cloud-like (MCL) configuration: a front region in which the magnetic field rotates and its magnitude declines, followed by a weakly rotating "back region" of nearly constant field magnitude. Near-Sun EUV and white-light observations reveal two fast CMEs launched in rapid succession and interacting at low coronal heights, providing direct evidence that an MCL ejecta can arise from interaction between two closely spaced CMEs sampled near their apex. Using near-radially aligned Solar Orbiter and STEREO-A observations, we find that the sheath expands more rapidly than the ME, consistent with the "snow-plow" effect, while the ME properties broadly follow trends reported in previous ICME studies. Comparison of STEREO-A and Wind observations, separated by only 9.2 degrees in longitude, reveals measurable mesoscale variability within both the sheath and the ME. We identify dual polytropic behavior within both substructures, consistent with the merging of two interacting CMEs to form the observed MCL ejecta. This dual behavior in the ME is most pronounced in the inner heliosphere and weakens with heliocentric distance, indicating thermodynamic homogenization during radial expansion, whereas the sheath maintains thermodynamic contrasts from the inner heliosphere to 1 au. Our findings suggest that polytropic diagnostics can help reveal thermodynamically distinct plasma populations associated with interacting CMEs, providing additional evidence for CME-CME interaction in MCL ejecta where conventional in-situ signatures show no clear evidence of such interactions.
Comments21 pages, 7 figures, 3 tables, accepted for publication in The Astrophysical Journal
