Radio-frequency excitation of harmonic microwave radiation from a Penning reflex discharge

Journal Article · Thu Apr 01 00:00:00 EST 1993 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860925· OSTI ID:6705980

Tate, J P; Wharton, C B ^[1]

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1. Laboratory of Plasma Studies, Cornell University, Ithaca, New York 14853 (United States)

Experimental results on multiple-harmonic emission at 8.8 GHz from a Penning reflex discharge (PRD) are reported. Observations of the frequency spectra of microwave emission showed copius harmonic generation of frequencies having two completely different origins: (1) spontaneously excited high harmonics of the electron cyclotron frequency and (2) high harmonics of the frequency of an injected signal independent of the magnetic field strength, a phenomenon reported here for the first time. For spontaneous harmonic emission there was a current threshold, whose magnitude depended on gas pressure and magnetic field strength. When a signal was injected, however, high harmonics (up to the 18th) could be seen at discharge currents well below this threshold value. Comparisons between the two types of radiation are made and discussion of possible mechanisms is provided. It is concluded that the coupling efficiency of the radio-frequency (rf)-excited emission is dependent on the relationship between the rf drive frequency and the electron cyclotron frequency. Finite Larmor radius effects may also influence this coupling. The plasma sheath size will also be a factor in the transfer of energy from the probe to the bulk plasma. Results which seek to elucidate these effects are presented.

• OSTI ID: 6705980
• Journal Information: Physics of Fluids B; (United States), Vol. 5:4; ISSN 0899-8221
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
PENNING DISCHARGES
MICROWAVE SPECTRA
ELECTRIC DISCHARGES
ELECTRON CYCLOTRON-RESONANCE
EXCITATION
HARMONIC GENERATION
LARMOR RADIUS
PLASMA SHEATH
PROBES
RADIOWAVE RADIATION
CYCLOTRON RESONANCE
ELECTROMAGNETIC RADIATION
ENERGY-LEVEL TRANSITIONS
FREQUENCY MIXING
RADIATIONS
RESONANCE
SPECTRA
700390* - Other Plasma Physics Studies- (1992-)