发表机构
Istituto per la Scienza e la Tecnologia dei Plasmi, Consiglio Nazionale delle Ricerche; Dipartimento di Fisica, Università della Calabria; Istituto Nazionale di Astrofisica, sede di Cosenza（等离子体科学与技术研究所，意大利国家研究委员会; 卡塔尼亚大学物理系; 意大利国家天体物理学研究所，科森扎分部）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究将小波基合成湍流模型扩展至非均匀膨胀太阳风，构建了含帕克螺旋场的高效磁湍流模型，可用于研究太阳高能粒子在日球层的传播。
AI 中文摘要
太阳高能粒子（SEP）在日球层中的传播受太阳风磁湍流的强烈影响，该湍流支配着粒子散射、场线游走和跨场输运，这些过程塑造了SEP的强度分布、各向异性和到达时间。由于日球层湍流跨越极宽的尺度范围，直接数值模拟无法捕捉其完整频谱，合成湍流模型通过生成具有规定统计和频谱特性的场提供了高效替代方案，使SEP输运的真实研究成为可能。本研究提出一种能够生成日球层合成磁湍流的数值模型，旨在研究场线和粒子扩散。该模型受原位太阳风观测启发，表明太阳风湍流特性随与太阳的距离变化。我们将笛卡尔小波基合成湍流模型（STM，由\uc810{Malara2016PhRvE..94e3109M}提出）扩展至非均匀膨胀的太阳风，方法是找到合适的坐标变换，使我们能从湍流相关长度均匀的空间转换至非均匀的空间。我们给出了推导过程、数值实现和测试结果，得到了一种改进且计算高效的合成湍流模型，其特征为具有背景帕克螺旋、宽惯性范围、相关长度和磁场涨落振幅的可调径向标度，以及可控的间歇性水平。该模型能够再现直至粒子拉莫尔尺度的太阳风湍流，并考虑太阳风的径向演化，使其成为研究SEP在整个日球层中传播的有力工具。
英文摘要
The propagation of Solar Energetic Particles (SEPs) through the heliosphere is strongly influenced by solar-wind magnetic turbulence, which governs particle scattering, field-line wandering, and cross-field transport. These processes shape SEP intensity profiles, anisotropies, and arrival times. Because heliospheric turbulence spans a vast range of scales, direct numerical simulations cannot capture its full spectrum. Synthetic turbulence models provide an efficient alternative by generating fields with prescribed statistical and spectral properties, enabling realistic studies of SEP transport. This work presents a numerical model able to generate synthetic magnetic turbulence in the heliosphere with the goal of studying field line and particle diffusion. The model is inspired by in situ solar wind observations, indicating that solar wind turbulence properties vary with the distance from the Sun. We extend the Cartesian wavelet-based Synthetic Turbulence Model (STM), presented in \cite{Malara2016PhRvE..94e3109M}, to the non-homogeneous expanding solar wind. This is achieved by finding a suitable change of coordinates that allows one to pass from a space in which the turbulence correlation length is homogeneous to one in which it is not. We present the analytical derivation, the numerical implementation, and testing. We obtain an improved and computationally efficient synthetic turbulence model characterized by a background Parker spiral, a broad inertial range and tunable radial scalings for both the correlation length and the magnetic-field fluctuation amplitude, as well as a controllable level of intermittency. The model capability of reproducing solar wind turbulence up to the particle Larmor scale and to take into account solar wind radial evolution makes it a powerful tool to study the propagation of SEPs throughout the heliosphere.
