Forecasting the geomagnetic effects of solar storms, known as coronal mass ejections (CMEs), is currently severely limited by our inability to predict the magnetic field configuration in the CME magnetic core and by observational effects of a single spacecraft trajectory through its 3‐D structure. CME magnetic flux ropes can lead to continuous forcing of the energy input to the Earth's magnetosphere by strong and steady southward‐pointing magnetic fields. Here we demonstrate in a proof‐of‐concept way a new approach to predict the southward field B_z in a CME flux rope. It combines a novel semiempirical model of CME flux rope magnetic fields (Three‐Dimensional Coronal ROpe Ejection) with solar observations and in situ magnetic field data from along the Sun‐Earth line. These are provided here by the MESSENGER spacecraft for a CME event on 9–13 July 2013. Three‐Dimensional Coronal ROpe Ejection is the first such model that contains the interplanetary propagation and evolution of a 3‐D flux rope magnetic field, the observation by a synthetic spacecraft, and the prediction of an index of geomagnetic activity. A counterclockwise rotation of the left‐handed erupting CME flux rope in the corona of 30° and a deflection angle of 20° is evident from comparison of solar and coronal observations. The calculated Dst matches reasonably the observed Dst minimum and its time evolution, but the results are highly sensitive to the CME axis orientation. We discuss assumptions and limitations of the method prototype and its potential for real time space weather forecasting and heliospheric data interpretation.

中文翻译：

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使用 3DCORE 对内日球层中的日冕物质抛射通量绳进行正演建模。


预测太阳风暴的地磁效应（称为日冕物质抛射 (CME)）目前受到严重限制，因为我们无法预测 CME 磁芯中的磁场配置，并且通过其 3D 结构观测单个航天器轨迹的影响。 CME 磁通绳可以通过强大而稳定的南向磁场持续迫使能量输入到地球磁层。在这里，我们以概念验证的方式展示了一种预测 CME 磁绳中向南磁场B _z的新方法。它将 CME 磁绳磁场（三维日冕绳抛射）的新型半经验模型与太阳观测和沿日地线的原位磁场数据相结合。这些是由信使号航天器为 2013 年 7 月 9 日至 13 日的日冕物质抛射事件提供的。三维日冕绳抛射是第一个包含 3 维磁力绳磁场的行星际传播和演化的此类模型，该模型由合成航天器，以及地磁活动指数的预测。从太阳和日冕观测结果的比较中可以看出，日冕中左手喷发的日冕物质抛射通量绳逆时针旋转了 30°，偏转角为 20°。计算出的Dst与观测到的Dst最小值及其时间演化合理匹配，但结果对 CME 轴方向高度敏感。我们讨论了该方法原型的假设和局限性及其在实时空间天气预报和日光层数据解释方面的潜力。