Sayram: A Positivity-Preserving Open Source 3D Radiation Belt Modeling Code

IF 2.6 2区 地球科学 Q2 ASTRONOMY & ASTROPHYSICS
Peng Peng, Xin Tao, Jay M. Albert, Anthony A. Chan
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引用次数: 0

Abstract

Radiation belt dynamics is typically modeled using a quasilinear diffusion equation. However, standard numerical methods often produce non-physical negative or oscillatory solutions due to cross-diffusion terms. Here, we present Sayram, an open-source 3D radiation belt modeling code that employs a positivity-preserving finite volume method to address this decades-old numerical challenge. Sayram incorporates key physical processes of the radiation belts, including local wave–particle interactions, radial diffusion, and losses due to precipitation and magnetopause shadowing. We validate Sayram using 1D radial diffusion, 2D pitch-angle and momentum diffusion, and a 3D model diffusion problem. Additionally, we apply it to a GEM challenge storm-time radiation belt event, demonstrating consistency with previous results. Compared to other 3D radiation belt codes, Sayram employs an implicit time integration scheme, preserves positivity, and ensures conservation properties. The code is developed in C++ with a highly modular design, allowing for easy adaptation to similar tasks. By making Sayram open source, we aim to provide the radiation belt community with a robust tool to improve radiation belt modeling and forecasting.

Sayram:一个保持正性的开源3D辐射带建模代码
辐射带动力学通常采用拟线性扩散方程建模。然而,由于交叉扩散项,标准数值方法经常产生非物理的负解或振荡解。在这里,我们提出Sayram,一个开源的三维辐射带建模代码,采用保正有限体积方法来解决这个几十年来的数值挑战。Sayram结合了辐射带的关键物理过程,包括局部波粒相互作用、径向扩散、降水和磁层顶遮蔽造成的损失。我们使用1D径向扩散、2D俯仰角和动量扩散以及3D模型扩散问题来验证Sayram。此外,我们将其应用于GEM挑战风暴时辐射带事件,证明了与先前结果的一致性。与其他三维辐射带代码相比,Sayram采用隐式时间积分方案,保留了正性,并确保了守恒性。代码是用c++开发的,具有高度模块化的设计,可以很容易地适应类似的任务。通过使Sayram开源,我们的目标是为辐射带社区提供一个强大的工具来改进辐射带的建模和预测。
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来源期刊
Journal of Geophysical Research: Space Physics
Journal of Geophysical Research: Space Physics Earth and Planetary Sciences-Geophysics
CiteScore
5.30
自引率
35.70%
发文量
570
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