Particle-in-Cell Simulation of Phase-Shift and Faraday Rotation in Interferometry-Polarimetry Diagnostic Device of ITER Fusion Plasma

Kinetic particle-in-cell (PIC) method is a reliable technique for the laser-plasma interactions simulation based on particles' statistical behavior. This method can be applied in simulating physical phenomena involved in optical diagnostics tools, such as the interferometry-polarimetry (IP) system. IP is one of the significant laser diagnostic methods suggested in the large tokamaks, such as international thermonuclear experimental reactor (ITER), as to improve the accuracy of density and magnetic field measurements. In this article, two separate simulations of the poloidal IP system are run by applying a 2-D/3-V XOOPIC code to observe the phase-shift and Faraday effect in a magnetized plasma with input density and poloidal magnetic field of n_e = 3.00 × 10¹⁹ m^-3 and B_p = 1.00 T, respectively. For this purpose, a gaseous (CO₂) linear-polarized far-infrared laser beam of λ_i = 118 μm wavelength, and about 30 W/m² intensity is passed through the plasma, parallel to the magnetic field. The density and poloidal magnetic field are computed from laser phase-shift and Faraday rotation theories, at n_e,com = 2.99 × 10¹⁹ m^-3 and B_p,com = 0.99 T, which correspond to the input values of these simulations. The obtained results indicate the competence and potency of the PIC method in simulating role-playing phenomena in ITER diagnostic devices like the IP system.