SEMIANNUAL REPORT ON PLASMA PHYSICS COVERING THE PERIOD JULY 1, 1962- DECEMBER 31, 1962

Technical Report · Wed Mar 13 00:00:00 EST 1963

OSTI ID:4145097

8 9 = ; 7 8 < : ; 8 5 E 9 8 were tested on the Model C stellarator showing good experimental and theoretical agreement. Equilibrium of a toroidal plasma with a conducting aperture limiter was also examined experimentally and theoretically. Measurements of floating potential differences at the bottom and top showed a pronounced positive potential peak. Studies of the effect of a helical field on plasma behavior showed the measured transform to agree well with the calculated values. Use of the absolute intensities of spectral lines in the vacuum ultraviolet region of stellarator emission for diagnostic purposes was examined; a vacuum monochromator device was used with acceptable results on the stellarator. A technique was developed for using the change in the ratio of the intensity of certain resonance multiplets of impurity ions to determine the electron temperature; tests using various impurity ions showed varying agreement with other determinations. Temperature determinations made using Doppler broadening of spectral lines compared well with the conductivity temperature at low currents. The vacuum ultraviolet monochromator was used to study the power loss due to impurity radiation; the power loss was compared to the input power. For a He discharge, between 30 and 100% of the input energy was lost as radiation. Current steps in the current trace of plasmas dominated by runaway electrons were examined. No appreciable chainge in cyclotron radiation was noted for step losses to the wall; for the absorption type of steps, the data support a model involving an electron-electron two stream instability. A 4-mm microwave interferometer was used to study the electron density distribution by measuring the propagation of the extraordinary mode. The dispersion curves compare favorably with graphs of a theoretical cold plasma dispersion relation. The return of the hydrogen gas that is removed during ohmic heating was also studied. Neutral gas return from the walls was found time dependent, and the percentage return proved small for several msec. The Etude device was used to investigate the presence of fluctuating electric fields transverse to the confining field as a cause of high electron loss during ohmic heating. The arrangement was deemed capable of accounting for ion diffusion across the magnetic field and for part of the electron diffusion. Experimental and theoretical curves for potential distribution made with the L-2 device agree well. Plasma heating by absorption of ion-cyclotron waves in a region of decreasing magnetic field was investigated in the B-66 device using diamagnetic probe measurements, an ion energy analyzer, and impurity measurements. The waves were concluded to heat deuterons to a temperature around 100 v. The Q-1 low-temperature Cs plasma device was used to study longitudinal trandsport phenomena. At low currents experimental and theoretical results agreed. Research on damping and propagation of ion acoustic waves in highly ionized plasmas gave evidence for collisionless damping of ion waves. Langmuir probes were used in and extensive study of space and timc dependence of the plasma density in a Stellarator. Results are graphed. Work in kinetic theory included development of a convergent classical kinetic equation for a plasma, derivation of a two-particle correlation function for an unstable plasma, investigation of charge neutrality for a Coulomb system in thermal equilibrium, and extension of the expansion for a weakly coupled spatial homogeneous system to fourth order. Stability studies dealt with the effect of a finite gyration radius on stellarator stability, the effect of finite conductivity on hydromagnetic instabilities, stability of hydromagnetic systems with dissipation, some results of quasi-linear theory, computer investigations of current instabilities, and the effects of viscosity and heat conductivity upon oscillations of current-carrying plasmas. The high-frequency conductivity of a plasma was also studied

• Research Organization: Princeton Univ., N.J. Plasma Physics Lab.
• DOE Contract Number: AT(30-1)-1238
• NSA Number: NSA-18-002981
• OSTI ID: 4145097
• Report Number(s): MATT-Q-20
• Resource Relation: Other Information: Orig. Receipt Date: 31-DEC-64
• Country of Publication: United States
• Language: English

Related Subjects

PHYSICS
ABSORPTION
ADIABATIC INVARIANCE
BREAKDOWN
C-STELLARATOR
CAPACITORS
COILS
COLLISIONS
COMPUTERS
CONFIGURATION
CURRENTS
CYCLOTRONS
DECAY
DENSITY
DEUTERONS
DIAMAGNETISM
DIFFUSION
DISPERSION RELATIONS
DISPERSIONS
DISTRIBUTION
ELECTRIC CHARGES
ELECTRIC CONDUCTIVITY
ELECTRIC DISCHARGES
ELECTRIC FIELDS
ELECTRIC POTENTIAL
ELECTROMAGNETIC WAVES
ELECTRONS
ELEMENTARY PARTICLES
EMISSION
ENERGY
EQUATIONS
FIELD THEORY
FREQUENCY
GASES
GLOW DISCHARGES
HEATING
HELIUM
HYDROGEN
IMPURITIES
INSTRUMENTS
INTERACTIONS
IONIZATION
IONS
LANGMUIR PROBE
LOSSES
MAGNETIC FIELDS
MAGNETISM
MAGNETOHYDRODYNAMICS
MEASURED VALUES
MI