Spatial and temporal evolutions of blue-core helicon discharge driven by a planar antenna with concentric rings
Year: 2025
Type: article
Abstract: We investigate the spatial and temporal dynamics of blue-core helicon discharge using a novel planar antenna with four concentric rings on the LEAD (Linear Experimental Advanced Device, JINST 15: P11002, 2020). As RF power increases, the discharge transitions through E, H, W, and blue-core modes at 1100 W, exhibiting a hollow density profile peaking off-axis. High-speed imaging reveals counterclockwise rotation in the blue-core mode (800 rad/s at 2000 W), contrasting with clockwise rotation in non-blue-core modes, driven by a radial electric field reversal. A two-fluid flowing plasma model predicts a centrifugal instability that is strongest at small axial wavenumbers, weakening as the wavenumber increases. The blue-core mode diminishes beyond thresholds of 2.0 Pa or 800 G. This study highlights unique density profiles and rotational dynamics, advancing the understanding of helicon plasma behavior.
Source: Physics of Plasmas
DOI: 10.1063/5.0280761
Authors: Chao Wang, Lei Chang, Ling-Feng Lu, Shunjiro Shinohara, Zhi-De Zeng, Ilya Zadiriev, Elena Kralkina, Zhi Li, Shi-Jie Zhang, Zi-Chen Kan, Ye Tao, Ding-Zhou Li
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W4416188297