Analysis of the Plasma Properties Affected by Magnetic Confinement with Special Emphasis on Helicon Discharges

A one-dimensional radial non-uniform fluid model is employed to study plasma behaviors with special emphasis laid on helicon discharges. The plasma density n_e, electron temperature T_e, electron azimuthal and radial drift velocities are investigated in terms of the plasma radius r_p, magnetic field intensity B₀ and gas pressure p₀, by assuming radial ambipolar diffusion and negligible ion cyclotron movement. The results show that the magnetic confinement plays an important role in the discharge equilibrium, especially at low pressure, which significantly reduces T_e compared with the case of a negligible magnetic field effect, and higher B₀ leads to a greater average plasma density. T_e shows little variations in the plasma density range of 10¹¹ cm⁻³–10¹³ cm⁻³ for p₀ < 3.0 mTorr. Comparison of the simulation results with experiments suggests that the model can make reasonable predictions of T_e in low pressure helicon discharges. (low temperature plasma)