1：Experimental Design and Method Selection:

The study uses the EMC3-EIRENE code for 3D edge plasma and impurity transport modeling in the LHD, incorporating Braginskii fluid equations for plasma and impurity transport, and Monte Carlo methods for steady-state solutions. The VUV spectrometer system is employed for experimental measurements of C3+ impurity flow via Doppler-shift spectroscopy.

2：Sample Selection and Data Sources:

Data from LHD discharge shot #126987 at specific timings (t = 3.25 s and t = 4.25 s) are used, with parameters such as magnetic axis position (Rax = 3.6 m), toroidal magnetic field (Bt = 2.75 T), upstream density, and input power from ECH and NBI heating.

3：25 s and t = 25 s) are used, with parameters such as magnetic axis position (Rax = 6 m), toroidal magnetic field (Bt = 75 T), upstream density, and input power from ECH and NBI heating. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment includes the Large Helical Device (LHD), VUV spectrometer system with CCD detector, mirrors, and computational tools like EMC3-EIRENE code and ADAS database for emission coefficients.

4：Experimental Procedures and Operational Workflow:

Simulations are set up with boundary conditions at LCFS, impurity sources from divertor erosion, and cross-field transport coefficients. VUV measurements involve capturing CIV spectra, fitting Gaussian profiles to determine Doppler shifts, and calculating impurity flow velocities.

5：Data Analysis Methods:

Data analysis includes post-processing with a program to compute chord-integrated velocities from simulations, comparing with experimental data, and performing parameter scans on magnetic configurations and plasma densities.