Nonlinear Effects in Low Frequency Inductive Plasmas
Abstract
Modern inductively coupled plasma (ICP) sources tend to operate at low frequencies (several MHz and less) that reduces capacitive coupling and transmission line effects and leads to simpler and lower cost rf power sources and matching circuits. Together with a low neutral gas pressure (1-10 mTorr) this creates a unique combination of conditions where two features of inductively coupled plasmas become most prominent: anomalous (non-collisional) heating and nonlinearity due to the Lorentz force. When the electrons are weakly collisional, the collisionless wave particle interaction (Landau damping) replaces real collisions and becomes the main mechanism of the wave absorption and plasma heating 1. In this regime, the electron mean free path exceeds the characteristic plasma length scale so that electrons "sample" the electric field over large distance resulting in the electric current being not a local function of the electric field. This regime is often referred to as nonlocal regime as opposite to the local, or short mean free path, highly collisional regime of the classical skin effect. The related property of the low frequency ICP is due to the fact that the nonlinear Lorentz force can be much larger than the force of the inductive electric field REGIME OF THE ELECTRON Hall magnetohydrodynamics (EMHD). Nonlinear forces in ICP may significantly affect plasma density profile 2, generate higher harmonics of the electric current 3, electrostatic potential 4,5, and modify the skin-effect 6. In this paper we review the experimental data and theoretical models describing these effects.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 20, 2003
- Accession Number
- ADP015044
Entities
People
- A. I. Smolyakov
- V. A. Godyak
- Yu. O. Tyshetskiy
Organizations
- University of Saskatchewan