ION DENSITY MEASUREMENTS IN A DECAYING HYDROGEN PLASMA

Technical Report · Wed Mar 01 04:00:00 EST 1961

OSTI ID:4060668

Cooper, III, W S; DeSilva, A W; Wilcox, J M

A hydrogen plasma was prepared for Alfven wave experiments and was allowed to decay. The shapes of the Stark broadened line profiles of the first three members of the Balmer series, H alpha , H beta , and H, were measured as functions of time and were matched with theoretical line profiles calculated by Griem, Kolb, and Shen to obtain the ion density as a function of time. In the 300 mu sec during which the line profiles were observed the ion density decayed from 5.0 x 10/sup 1//sup 5/ cm/sup -//sup 3/, to 1.5 x 10/sup 1//sup 5/ cm/sup -// sup 3/, and extrapolated backto 5.5 x 10/sup 1//sup 5/ to 7.1 x 10/sup 1//sup 5/ cm/sup -//sup 3/ at the time the discharge current was terminated, corresponding to 85 to 100% ionization of the hydrogen initially in the tube. A nearly pure Balmer spectrum, merging with the continuum after nine lines, was observed. The observed depression of the series limit indicated a time-averaged ion density of about 3 x 10/sup 1//sup 5/ cm/sup -//sup 3/ in good agreement with the measurements from the profiles of the three individual lines. The observed velocity of Alfven waves in the plasma yielded a value for the ion density that was also in good agreement with these spectroscopically determined values. The temperature was estimated to be about 10,000 deg K. The plasma probably decays by a volume recombination process in the manner described by D'Angelo. (auth)

• Research Organization: California. Univ., Berkeley. Lawrence Radiation Lab.
• DOE Contract Number: W-7405-ENG-48
• NSA Number: NSA-15-020256
• OSTI ID: 4060668
• Report Number(s): UCRL-9509
• Country of Publication: United States
• Language: English

Related Subjects

ALFVEN WAVES
BALMER LINES
DECAY
DENSITY
HYDROGEN
IONS
PHYSICS
PLASMA
PLASMA WAVES
SPECTRA
SPECTROSCOPY