INSTABILITY OF AN ALTERNATING-CURRENT POSITIVE COLUMN IN A MAGNETIC FIELD (thesis)

Technical Report · Mon Apr 22 04:00:00 EST 1963

OSTI ID:4687527

Rugge, H F

The positive column of a glow discharge in a magnetic field is known to become macroscopically unstable at some critical magnetic field, B/sub c/. Kadomtsev's proposed driving mechanism for this helical (m = 1) instability is such thnt if one periodically reverses the axial electric field at a frequency greater than the growth rate of the instability, one would expect it to be suppressed. A detailed study of the instability was made in d-c half- waverectified (unidirectional) current, and square and sinusoi, dal a-c glow discharges in H/sub 2/, D/sub 2/, He, Ne, and Ar. The study of the d-c discharges corroborated previous results and yielded experimental parameters necessary for comparison with theory. Electron-temperature measurements at B = 0 and near the critical magnetic field were obtained by employing single- and double-probe techniques. Halfwave rectified discharges over a wide range of frequencies yielded instabilities whose onset (B/sub 2/) and helical nature duplicated those of the direct-current discharges. However, the instability in the alternating-current discharges was found to be suppressed as the electric- field reversal frequency was increased; this substantiates the Kadomtsev model of the driving mechanism. The frequency-dependent suppression of the alternating- current instability is compared with the theoretical growth rates. The effect of several m-value modes is calculated, and results show good qualitative agreement. Good quantitative agreement is obtained when the Johnson and Jerde modification of the Kadomtsev theory is employed. 49 references. (auth)

• Research Organization: California. Univ., Berkeley. Lawrence Radiation Lab.
• DOE Contract Number: W-7405-ENG-48
• NSA Number: NSA-17-033161
• OSTI ID: 4687527
• Report Number(s): UCRL-10698
• Country of Publication: United States
• Language: English

Related Subjects

ARGON
BIBLIOGRAPHY
CURRENTS
DEUTERIUM
ELECTRIC CHARGES
ELECTRIC FIELDS
ELECTRONS
FREQUENCY
GLOW DISCHARGES
HELICAL INSTABILITY
HELIUM
HYDROGEN
KINK INSTABILITY
MAGNETIC FIELDS
MEASURED VALUES
NEON
NUMERICALS
PERFORMANCE
PHYSICS
PINCH
PLASMA
PROBES
STABILITY
TEMPERATURE