Effects of radial temperature and pressure distribution on energy distribution and wave field in helicon plasma

The steady-state process of RF-heated plasma was studied. Under the conditions of parabolic distribution and Gaussian distribution of plasma density, the radial pressure and temperature gradient were analyzed for the influence of power deposition and electric field and the distribution of current density in the two-density distribution of helicon plasma. Three gradient models were considered: positive gradient, negative gradient and zero gradient. Studies have shown that positive temperature gradients are more conducive to the absorption of power at the center of the plasma. The positive pressure gradient increases the induced electric field at the edge of the plasma, reduces the current density at the center, and weakens the power deposition at the edge. The wave energy coupling depth is deepened, which is more conducive to the coupling absorption of power at the center. Under the Gaussian density distribution, the electric field intensity is higher at the edge of the plasma, and the current density is smaller. The deposition energy of the radio frequency wave at the edge position is less and the change is not large, and the coupling depth of the wave energy is greatly increased. Under the parabolic density distribution, the power deposition at the center and the edge of the plasma is large, and the power deposition near the edge is particularly prominent and significantly higher than that under the Gaussian density distribution.It was found that the three temperature and pressure distributions have similar effects on the electric field strength and current density distribution and the change trend in the plasma of the two density structures, thus demonstrating the stability of the m=1 mode.