Solar Energetic Particle Modelling for Space Weather

在耀斑和日冕物质抛射（CME）期间，高能太阳粒子在太阳附近加速，对太空中的人类和卫星设备构成威胁。该项目将开发这些太阳高能粒子（sep）在太空中的加速和传播的新模型。到目前为止，大多数旨在预测太阳活动后sep强度的模拟都假设这些粒子倾向于保持“捆绑”在磁场上，与磁场平行移动。然而，最近来自尤利西斯号宇宙飞船和其他任务的数据表明，粒子可以有效地跨越磁力线。这种被称为跨场扩散的现象很可能对我们预测有多少粒子在耀斑或日冕物质抛射后到达空间中的给定位置有很大的影响。在这个项目中，我们将在描述SEP加速和传播的代码中包括跨场扩散。我们将在一台超级计算机上运行我们的代码，以尽量减少其运行时间，并将使用不同的跨场扩散模型获得的结果与孪生STEREO航天器的数据进行比较，以选择最能描述数据的模型。我们的工作将用于预测sep对宇航员的危害，作为所谓的太空天气研究的一部分。

High energy solar particles accelerated at the Sun during flares and Coronal Mass Ejections (CME) pose a threat to humans and satellite equipment in space. This project will develop new models of the acceleration and propagation through space of these Solar Energetic Particles (SEPs). Up to now, the majority of simulations aimed at predicting the intensity of SEPs following a solar event have assumed that the particles tend to remain 'tied' to the magnetic field, moving parallel to it. However, recent data from the Ulysses spacecraft and other missions have shown that particles can efficiently jump across magnetic field lines. This phenomenon, called cross-field diffusion, is likely to have a strong effect on our predictions of how many particles will reach a given location in space following a flare or CME. In this project we will include cross-field diffusion in a code that describes SEP acceleration and propagation. We will run our code on a supercomputer, to minimise its running time, and will compare the results obtained using different models of cross-field diffusion with data from the twinned STEREO spacecraft, to choose the model that best describes the data. Our work will be applied to predicting the hazard to astronauts from SEPs, as part of studies of so-called Space Weather.