The basics of focused transport as applied to solar energetic particles are reviewed, paying special attention to areas of common misconception. The micro-physics of charged particles interacting with slab turbulence are investigated to illustrate the concept of pitch-angle scattering, where after the distribution function and focused transport equation are introduced as theoretical tools to describe the transport processes and it is discussed how observable quantities can be calculated from the distribution function. In particular, two approximations, the diffusion-advection and the telegraph equation, are compared in simplified situations to the full solution of the focused transport equation describing particle motion along a magnetic field line. It is shown that these approximations are insufficient to capture the complexity of the physical processes involved. To overcome such limitations, a finite-difference model, which is open for use by the public, is introduced to solve the focused transport equation. The use of the model is briefly discussed and it is shown how the model can be applied to reproduce an observed solar energetic electron event, providing insights into the acceleration and transport processes involved. Past work and literature on the application of these concepts are also reviewed, starting with the most basic models and building up to more complex models.
A study of solar energetic particle transport on 30 March 2022 using multi-spacecraft data assimilation
Japan Agency for Marine-Earth Science and Technology（日本海洋地球科学技术局）；Nagoya University（名古屋大学）；Kyung Hee University（庆熙大学）；Japan Aerospace Exploration Agency（日本宇宙航空研究开发机构）；European Space Agency（欧洲空间局）；Austrian Academy of Sciences（奥地利科学院）；Kyoto University（京都大学）
Connection-angle dependence of proton anisotropy in ground-level enhancement events
Heliophysics Division, NASA Goddard Space Flight Center（NASA 戈达德太空飞行中心日物理部）；Catholic University of America（美国天主教大学）；Jeremiah Horrocks Institute, University of Lancashire（兰开夏大学杰里迈亚·霍罗克斯研究所）
