Complex Coronal Mass Ejection Structures and Associated Geo-effectiveness

太阳是整个日光层物理特性的最终驱动者，由于太阳大气层中发生的大规模动态事件，如日冕物质抛射（CME），太阳可能对近地空间环境造成严重扰动。我们的社会越来越依赖可能被这些所谓的空间气象事件直接破坏的技术资产。 因此，预测这类事件的发生和详细性质对于尽量减少其损害至关重要。 如果CME在穿过行星际介质的途中遇到其他大尺度结构，例如其他CME，那么决定其对地球影响的CME特征可能会发生急剧变化。 统计研究表明，相互作用的日冕物质抛射形成所谓的复杂喷出物结构，是最强烈空间天气事件的一个重要来源。 该项目旨在调查这些相互作用可能发生的多种方式，并揭示由此产生的复杂喷出物特征和空间气象影响。 反过来，这将有助于更好地了解和预测一些最大的地磁暴的形成，该项目包括重要的科学教育和公众宣传部分。PI和提案团队的其他成员是在线网站www.solarstormwatch.com的贡献者，这是一个有公民参与的实时预测网站。 作为该项目的一部分，他们将继续参与，除其他外，通过开发供公众传播的补充材料，包括三维可视化和多媒体材料。 还包括资助本科生参加研究项目。该项目的总体目标是深入研究与多个相互作用的日冕物质抛射或日冕物质抛射与其他太阳风气流相互作用有关的复杂现象，重点是观察到的效应背后的物理学及其产生的地球效应潜力。这将通过以下方式实现：（i）用最先进的理想化情况下的MHD代码进行3-D数值模拟，（ii）对选定的真实的研究进行组合的3-D数值模拟和数据分析，以及（iii）对现场测量进行分析。 具体而言，生成白光图像和现场测量的能力将使研究中的观测效应能够在分析复杂事件时纳入，并通过模拟和观测之间的直接比较来验证数值结果。 调查将解决以下科学问题：1）CME-CME相互作用的不同表现形式是什么远程观察和现场测量？它们的起源是什么 2)连续的日冕物质抛射的相互作用是如何压缩、加速、偏转和旋转日冕物质抛射的？3)CME-CME相互作用与CME-CIR相互作用有何异同？4)是什么让复杂的喷出物和化合物流如此具有地理效益？

The Sun is the ultimate driver of the physical properties of the entire Heliosphere, and can cause severe perturbations to the near-Earth space environment due to large-scale dynamic events taking place in the solar atmosphere, such as Coronal Mass Ejections (CMEs). Our society is becoming increasingly dependent on technological assets that can be directly damaged by these, so-called, space weather events. Consequently, predicting the occurrence and detailed nature of such events is of critical importance to minimizing their damage. The characteristics of CMEs that determine their impact at Earth can change drastically if the CMEs encounter other large-scale structures on their way through the interplanetary medium, such as other CMEs. Statistical studies indicate that interacting CMEs, creating so-called complex ejecta structures, are an important source for the most intense space weather events. This project aims to investigate a multitude of ways in which these interactions can happen and reveal the resulting complex ejecta characteristics and space weather impacts. In turn, this will contribute towards better understanding and predicting the formation of some of the largest geomagnetic storms.The project includes significant science education and public outreach components. The PI and other members of the proposal team are contributors to the online website www.solarstormwatch.com, a website for real-time prediction with citizen involvement. They will continue this engagement as part of this project, amongst other through the development of complementary materials for public dissemination, including 3-D visualizations and multimedia materials. Funding is also included for the participation of undergraduate students in the research project. The overarching goal of this project is to carry out an in-depth study of complex phenomena associated with multiple, interacting CMEs or CMEs interacting with other solar wind streams, focusing on the physics behind the observed effects, and their resulting geo-effective potential. This will be done through: (i) 3-D numerical simulations with a state-of-the-art MHD code of idealized situations, (ii) combined 3-D numerical simulations and data analysis of selected real studies, and, (iii) analysis of in-situ measurements. Specifically, the ability to generate white-light images and in situ measurements will enable the inclusion of observational effects in the study when analyzing complex events and the validation of the numerical findings by direct comparisons between simulations and observations. The investigation will address the following science questions: 1) What are the different manifestations of CME-CME interaction observed remotely and measured in-situ? and what is their origin? 2) How does the interaction of successive CMEs compress, accelerate, deflect and rotate the CMEs? 3) What are the similarities and differences between CME-CME interaction and CME-CIR interaction? 4) What makes complex ejecta and compound streams so geo-effective?