SOME MEASUREMENTS OF STEADY AND FLUCTUATING PLASMA NUMBER DENSITIES BY A MICROWAVE METHOD

Technical Report · Mon Oct 01 04:00:00 EDT 1962

OSTI ID:4748763

Crawford, F W; Kino, G S; Self, S A; Spalter, J

Measurements of d-c and a-c components of number density along the positive columns of hot-cathode, mercuryvapor discharges, at a presusre of about 1 mu Hg, were made by a microwave method. The technique is based on a dipole resonance, occurring below the electron plasma frequency, which is excited by an r-f signal transmitted along a strip-line enclosing the plasma column. By working on the side of the resonance curve, a fluctuating output signal is obtained corresponding to the density fluctuations. The simple theory of the resonance has been extended to take account of strip-line size, of the glass surrounding the column, and of a radial variation in number density. The method is considerably more sensitive than cavity perturbation techniques, and the results compare reasonably well with number density measurements made by other methods. It is found that the frequency spectrum of fluctuations is similar to those of the potential and light output fluctuations; that there are similarities in the distribution along the column of the amplitudes of these quantities; and that for injected a-c signals, the phase and amplitude variation of the number density are as predicted theoretically. (auth)

• Research Organization: Stanford Univ., Calif. Microwave Lab.
• NSA Number: NSA-17-015352
• OSTI ID: 4748763
• Report Number(s): TID-17791; ML-961
• Country of Publication: United States
• Language: English

Related Subjects

CATHODES
CIRCUITS
CONFIGURATION
CURRENTS
DENSITY
DIPOLES
DISTRIBUTION
ELECTRIC DISCHARGES
ELECTRIC POTENTIAL
ELECTRONS
EMISSION
EXCITATION
FREQUENCY
GLASS
INJECTION
LIGHT
MEASURED VALUES
MERCURY
MICROWAVES
PHYSICS
PLASMA
PRESSURE
RADIO WAVES
RESONANCE
SIGNALS
SPECTRA
STABILITY
VAPORS
VARIATIONS