Speaker
Description
Analyzing charged particle transport near a magnetic X-point in the presence of neutral species is crucial for understanding and controlling tokamak plasmas. To study plasmas in a similar environment, a steady-state, low-temperature plasmas are generated in the MAgnetic X-poInt siMUlator System (MAXIMUS) [1] using a DC-heated cathode. Langmuir probes are utilized to obtain spatially resolved electron energy distribution function (EEDF) profiles near the magnetic X-point under various plasma conditions. From the electron density and temperature measured around the magnetic X-point, the collisional source and sink terms for the continuity equation are calculated using the ionization cross section [2] and the recombination rates [2,3]. The differential term in the continuity equation is also evaluated from the electron density profile, assuming Fick’s law and a steady-state condition. Consequently, the diffusion coefficient in Fick’s law can be estimated. In this work, we present experimentally determined diffusion coefficients around the magnetic X-point in MAXIMUS under various plasma conditions.
This work was supported by National Grant no. RS-2022-00155917 and NRF-2021R1A2C2005654.
References
[1] Lim, Yegeon, et al. "New low temperature multidipole plasma device with a magnetic X-point and its properties." Plasma Sources Science and Technology 29.11 (2020): 115012.
[2] Bogaerts, Annemie, Renaat Gijbels, and Jaroslav Vlcek. "Collisional-radiative model for an argon glow discharge." Journal of applied physics 84.1 (1998): 121-136.
[3] Li, C. Y., Y. Z. Qu, and J. G. Wang. "State-selective radiative recombination cross sections of argon ions." Journal of Quantitative Spectroscopy and Radiative Transfer 113.15 (2012): 1920-1927.