Plasma phenomena in inductive discharges

Abstract

In this paper, recent advances in the physics of low pressure inductively coupled plasmas (ICPs) are reviewed where the interaction of an electromagnetic field with electrons is governed by electron thermal motion rather than electronatom collisions. Direct measurement of the rf electric field and rf current density in the plasma made it possible to distinguish between collisional and stochastic (collisionless) electron heating. Several new phenomena such as a wave phase bifurcation, phase velocity reversal, a second current layer and negative power absorption have been found and interpreted in terms of nonlocal electrodynamics. Nonlinear effects induced by the rf Lorentz force such as nonlinear plasma polarization and second harmonic currents, as well as modification of the spatial distribution of the plasma caused by ponderomotive forces have been demonstrated in ICP under discharge conditions typical for industrial applications.

Nonlocal conductivity effects in low-pressure cylindrical inductive discharges

“…Connected to the changes and a jump of the phase. The spatial distribution of the amplitude and the phase obtained in cylindrical discharges is in the trends of that discussed [4] in discharges with planar configuration, confirming that the nonmonotonic changes of the amplitude of the field and the jump of its phase outline general behaviour within the nonlocal electrodynamics. The frequency dependence of the effects can be related to the presence of a "second wall" in the discharge which provides conditions for a resonance of the wave field with the bounce motion of the electrons across the total cross section of the discharge.…”

“…The electrons gain momentum in the rf heating field close to the discharge walls and transfer it -through their thermal motion -into the plasma interior. The local relation E j σ = between current density ) (j and electric field ) (E is not valid anymore and the current density at a given position is determined by the electric field over the entire trajectory of the electron on the distance of its mean free path: [1,4,5] in the field is stochastic (collisionless) and the description is within the kinetic plasma theory.…”

“…The research on the rf power deposition in low-pressure inductive discharges [4][5][6] has revived the studies [7][8][9] on anomalous skin and nonlocal conductivity in the late 60's and the early 70's and involved them in the discharge modelling. However, the work up to now has covered only inductive discharges with planar coils, i.e.…”

Density profile sensitivity study of ASDEX Upgrade ICRF Antennas with the TOPICA code

“…Within the simplest RF sheath models [2,3,4], ICRF antenna drives an oscillating RF potential V RF between the ends of open flux tubes in vicinity of the launcher. The RF potential is given by integration along the open magnetic field lines V RF = ∫ E // dl, where E // is the RF parallel electric field.…”

Plasma modeling for a nonsymmetric capacitive discharge driven by a nonsinusoidal radio frequency current

“…Various authors have developed models to account for the electron and ion dynamics within the sheaths. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] However, the nonlinear ion and electron dynamics are not treated self-consistently within these models. Lieberman developed an analytical, selfconsistent solution for the collisionless rf sheath considering a single sinusoidal rf current.…”