Central peaking of magnetized gas discharges
- Electrical Engineering Department, University of California, Los Angeles, California 90095 (United States)
- Department of Nuclear, Plasma and Radiological Engineering, University of Illinois at Urbana Champaign, Urbana, Illinois 61801 (United States)
Partially ionized gas discharges used in industry are often driven by radiofrequency (rf) power applied at the periphery of a cylinder. It is found that the plasma density n is usually flat or peaked on axis even if the skin depth of the rf field is thin compared with the chamber radius a. Previous attempts at explaining this did not account for the finite length of the discharge and the boundary conditions at the endplates. A simple 1D model is used to focus on the basic mechanism: the short-circuit effect. It is found that a strong electric field (E-field) scaled to electron temperature T{sub e}, drives the ions inward. The resulting density profile is peaked on axis and has a shape independent of pressure or discharge radius. This “universal” profile is not affected by a dc magnetic field (B-field) as long as the ion Larmor radius is larger than a.
- OSTI ID:
- 22228120
- Journal Information:
- Physics of Plasmas, Vol. 20, Issue 5; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Formation and maintenance of a tokamak discharge via dc helicity injection
One-dimensional time-dependent fluid model of a very high density low-pressure inductively coupled plasma