论文标题
Euhforia的FRI3D磁通绳模型的实施和验证
Implementation and validation of the FRi3D flux rope model in EUHFORIA
论文作者
论文摘要
3D（FRI3D，ISAVNIN，2016年）中的通量绳，这是一种具有全球三维几何（3D）几何形状的冠状质量弹出（CME）模型，已在太空天气预测工具Euhforia（Pomoell and Poedts，2018年）中实现。通过在Euhforia结合这种高级通量绳模型，我们旨在改善CME侧面相遇的建模，最重要的是，在地球上进行了磁场预测。在使用合成事件来展示FRI3D建模CME侧面的功能之后，我们优化了模型以运行真实事件的可靠模拟并测试其预测能力。我们对2012年7月12日爆发的Halo CME事件进行了基于观察的建模。使用FRI3D中包含的正向建模工具限制了几何输入参数，并具有与预先存在的模型相比，具有附加的磁通绳几何体挠性。磁场输入参数是使用差分进化算法得出的，以将FRI3D参数拟合到1 AU处的原位数据。为了更好地估计与FRI3D几何形状相对应的质量，采用了一种基于观测的方法来限制CME的密度。 CME在Euhforia的Heliosperic结构域中演变，并提出了FRI3D的预测性能与Euhforia先前实现的Spheromak CME的比较。对于此事件，FRI3D分别将地球总磁场幅度和BZ的建模分别提高了〜30％和〜70％。此外，我们使用经验DST模型来计算地球风暴的预期地理效果，并发现与Spheromak CME模型相比，FRI3D模型将最小DST的预测提高了约20％。最后，我们讨论了FRI3D在Euhforia的当前实施的局限性，并提出了可能的改进。
The Flux Rope in 3D (FRi3D, Isavnin, 2016), a coronal mass ejection (CME) model with global three-dimensional (3D) geometry, has been implemented in the space weather forecasting tool EUHFORIA (Pomoell and Poedts, 2018). By incorporating this advanced flux rope model in EUHFORIA, we aim to improve the modelling of CME flank encounters and, most importantly, the magnetic field predictions at Earth. After using synthetic events to showcase FRi3D's capabilities of modelling CME flanks, we optimize the model to run robust simulations of real events and test its predictive capabilities. We perform observation-based modelling of the halo CME event that erupted on 12 July 2012. The geometrical input parameters are constrained using the forward modelling tool included in FRi3D with additional flux rope geometry flexibilities as compared to the pre-existing models. The magnetic field input parameters are derived using the differential evolution algorithm to fit FRi3D parameters to the in situ data at 1 AU. An observation-based approach to constrain the density of CMEs is adopted, in order to achieve a better estimation of mass corresponding to the FRi3D geometry. The CME is evolved in EUHFORIA's heliospheric domain and a comparison of FRi3D's predictive performance with the previously implemented spheromak CME in EUHFORIA is presented. For this event, FRi3D improves the modelling of the total magnetic field magnitude and Bz at Earth by ~30% and ~70%, respectively. Moreover, we compute the expected geoeffectiveness of the storm at Earth using an empirical Dst model and find that the FRi3D model improves the predictions of minimum Dst by ~20% as compared to the spheromak CME model. Finally, we discuss the limitations of the current implementation of FRi3D in EUHFORIA and propose possible improvements.
