Spatial profiling of ion and neutral excitation in noble gas electron cyclotron resonance plasmas

Journal Article · Mon Oct 17 04:00:00 EDT 1994 · Applied Physics Letters; (United States)

DOI:https://doi.org/10.1063/1.112844· OSTI ID:7138374

Rhoades, R L; Gorbatkin, S M ^[1]

---

1. Oak Ridge National Laboratory, Solid State Division, P. O. Box 2008, MS 6057, Oak Ridge, Tennessee 37831-6057 (United States)

Optical emission from neutrals and ions of several noble gases has been profiled in an electron cyclotron resonance plasma system. In argon plasmas with a net microwave power of 750 W, the neutral (696.5-nm) and ion (488-nm) emission profiles are slightly center peaked at 0.32 mTorr and gradually shift to a hollow appearance at 2.5 mTorr. Neon profiles show a similar trend from 2.5 to 10.0 mTorr. For the noble gases, transition pressure scales with the ionization potential of the gas, which is consistent with neutral depletion. Studies of noble gas mixtures, however, indicate that neutral depletion is not always dominant in the formation of hollow profiles. For Kr/Ar, Ar/Ne, and Ne/He plasmas, the majority gas tends to set the overall shape of the profile at any given pressure. For the conditions of the current system, plasma density appears to be more dominant than electron temperature in the formation of hollow profiles. The general method described is also a straightforward, inexpensive technique for measuring the spatial distribution of power deposited in plasmas, particularly where absolute scale can be calibrated by some other means.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 7138374
• Journal Information: Applied Physics Letters; (United States), Journal Name: Applied Physics Letters; (United States) Vol. 65:16; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700320* -- Plasma Diagnostic Techniques & Instrumentation-- (1992-)
700350 -- Plasma Production
Heating
Current Drive
& Interactions-- (1992-)
DENSITY
DISTRIBUTION
ECR HEATING
ELECTRIC DISCHARGES
ELEMENTS
EMISSION SPECTRA
FLUIDS
GASES
HEATING
HIGH-FREQUENCY DISCHARGES
HIGH-FREQUENCY HEATING
IONIZATION
NONMETALS
PHYSICAL PROPERTIES
PLASMA DIAGNOSTICS
PLASMA HEATING
PRESSURE DEPENDENCE
RARE GASES
SPATIAL DISTRIBUTION
SPECTRA
VISIBLE SPECTRA