Electron Energy Distributions in Plasmas. V. A Search for Evidence of a High Anomalous Rate of Energy Exchange between the Electrons of a Low-Pressure Discharge

Journal Article · Tue Oct 08 04:00:00 EDT 1963 · Proceedings of the Royal Society. A. Mathematical, Physical and Engineering Sciences

DOI:https://doi.org/10.1098/rspa.1963.0174· OSTI ID:4625058

Twiddy, N. D.

\Since earlier measurements of electron energy distributions obtained with the Druyvesteyn probe method showed no evidence of the scattering observed in mercury by Langmuir (1925) and Merrill & Webb (1939), the method was used to examine discharges in hydrogen, neon, krypton, and mercury in a search for evidence of such a high rate of energy exchange between the electrons. This was observed in neon when, as the discharge current was increased, the well-defined group of primary electrons from the filament disappeared, giving rise to a uniform distribution. In krypton and mercury, the distribution near the filament was usually uniform, although frequently there was evidence of a strongly broadened primary group and electrons were often observed with energies greater than the potential difference between the filament and the measuring probe. This behavior is almost certainly to be explained in terms of Langmuir scattering near the filament, but the scattering was always restricted to regions very close to the filament and was never observed in the positive column. After the initial scattering the distribution is influenced by the applied field in a similar manner to that observed in earlier measurements and in these gases, although the distribution is quite uniform near the filament, there are very marked departures from uniformity further from the cathonde as the distribution is accelerated in either a uniform field or through a step of potential, giving rise to well defined primary and secondary groups of electrons. These newly created primaries are not scattered. Measurements in high-field regions in krypton show a high ratio of primary to secondary electrons. This is due to the pronounced Ramsauer effect in this gas and was observed earlier in argon. The change of energy distribution resulting from the contamination of a discharge in neon by argon and mercury was investigated.

• Research Organization: University Coll., London
• Sponsoring Organization: USDOE
• NSA Number: NSA-17-042125
• OSTI ID: 4625058
• Journal Information: Proceedings of the Royal Society. A. Mathematical, Physical and Engineering Sciences, Journal Name: Proceedings of the Royal Society. A. Mathematical, Physical and Engineering Sciences Journal Issue: 1362 Vol. 275; ISSN 1364-5021
• Publisher: The Royal Society Publishing
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ARGON
CATHODES
CONTAMINATION
CURRENTS
DISTRIBUTION
ELECTRIC DISCHARGES
ELECTRIC POTENTIAL
ELECTRON BEAMS
ELECTRON TEMPERATURE
ELECTRONS
ENERGY
GASES
HOMOGENEOUS REACTORS
HYDROGEN
INTERACTIONS
KRYPTON
LOSSES
MEASURED VALUES
MERCURY
NEON
PLASMA
PLASMA DIAGNOSTICS
PRESSURE
RAMSAUER EFFECT
SCATTERING
SECONDARY EMISSION
TESTING
VELOCITY
WIRES