Millimeter-wave interferometer for measuring plasma electron density

Journal Article · Mon Aug 01 00:00:00 EDT 1988 · Rev. Sci. Instrum.; (United States)

DOI:https://doi.org/10.1063/1.1140153· OSTI ID:6822458

Domier, C W; Peebles, W A; Luhmann, Jr, N C

A simple, low-cost millimeter-wave interferometer has been developed to measure the electron density of laboratory-type plasmas with densities nless than or equal to2 x 10/sup 12/ cm/sup -3/ . Two 38.0-GHz Gunn oscillators, whose oscillation frequencies are offset by 40 MHz, are used in a heterodyne configuration. The high intermediate frequency allows the use of inexpensive, free-running mechanically tuned Gunn oscillators and permits this system to be utilized in the study of density fluctuations. A quadrature phase comparator is used to give simultaneously both the sine and cosine components of the plasma interference signal. The phase noise of the system is found to be <0.1/sup 0/, with a settling time <100 ns. The system is to be used on a laboratory plasma to look at both the integrated electron density and the level of density fluctuations.

• Research Organization: Institute of Plasma and Fusion Research, University of California, Los Angeles, California 90024
• OSTI ID: 6822458
• Journal Information: Rev. Sci. Instrum.; (United States), Vol. 59:8
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
PLASMA DIAGNOSTICS
INTERFEROMETERS
DESIGN
ELECTRON DENSITY
FAR INFRARED RADIATION
PERFORMANCE TESTING
SIGNAL-TO-NOISE RATIO
ELECTROMAGNETIC RADIATION
INFRARED RADIATION
MEASURING INSTRUMENTS
RADIATIONS
TESTING
700102* - Fusion Energy- Plasma Research- Diagnostics