I02_par_init_and_load

模块职责

I02_par_init_and_load 面向需要离线生成初始粒子文件的算例。Python 脚本先根据解析密度模型在三维 T 形区域中生成电子和离子的 x,y,z,vx,vy,vz 记录；Fortran 载入例程再在 MPI 运行时读取这些二进制记录，并按本地子域范围筛选粒子。

文件
文件	说明
init_particles_bin.py	离线生成 `output_init_particles_bin/par_ele_init.bin` 和 `par_ion_init.bin`，并输出诊断图。
mod_I02_load_init_particles_bin.f90	Fortran 模块包装器，暴露二进制粒子载入例程。
sub_I02_load_init_particles_bin.f90	MPI 并行载入二进制粒子文件并分配到当前 rank。

数据流

在准备阶段运行 init_particles_bin.py，生成全局粒子二进制文件。
MPI 程序启动后，每个 rank 调用载入例程并顺序扫描全局文件。
载入例程只保留满足 il(d)-1 <= r(d) < iu(d) 的粒子。
所有 rank 用 MPI_Allreduce 得到跨物种的本地最大粒子数，并按 f_npmax 扩展分配 par。

应用文献

该离线初始粒子生成和载入流程用于 Hall 推力器三维 PIC 模拟中的近壁输运研究。相关论文包括：

Z. Liu, Z. Zhao, and Y. Zhao, Near-Wall Pathways of Anomalous Electron Transport in Hall Thrusters Revealed by 3D PIC Simulations, arXiv:2603.14849 [physics.plasm-ph] (2026). DOI: 10.48550/arXiv.2603.14849.

Module Role

I02_par_init_and_load supports cases that prepare initial particles through offline binary files. The Python script generates electron and ion x,y,z,vx,vy,vz records in a three-dimensional T-shaped region from analytical density and velocity models; the Fortran loader then reads those records during MPI startup and keeps the particles owned by the local subdomain.

Files
File	Description
init_particles_bin.py	Offline generator for `output_init_particles_bin/par_ele_init.bin` and `par_ion_init.bin`, plus diagnostic plots.
mod_I02_load_init_particles_bin.f90	Fortran module wrapper exposing the binary particle loader.
sub_I02_load_init_particles_bin.f90	MPI loader that reads binary particle files and assigns particles to the current rank.

Data Flow

Run init_particles_bin.py during case preparation to generate global binary particle files.
During MPI startup, each rank calls the loader and scans the global files.
The loader keeps only particles satisfying il(d)-1 <= r(d) < iu(d).
The ranks use MPI_Allreduce to find the local maximum particle count and allocate par with the f_npmax expansion factor.

Applications and References

This offline initial-particle generation and loading workflow is used in a near-wall transport study for Hall-thruster 3D PIC simulations. Related papers include:

Z. Liu, Z. Zhao, and Y. Zhao, Near-Wall Pathways of Anomalous Electron Transport in Hall Thrusters Revealed by 3D PIC Simulations, arXiv:2603.14849 [physics.plasm-ph] (2026). DOI: 10.48550/arXiv.2603.14849.