Investigation of r-f emissions from electric-field-dominated plasmas. Final scientific report, 31 January 1980-31 March 1989

Technical Report · Fri Mar 31 04:00:00 EST 1989

OSTI ID:5593633

Roth, J R

Research includes efforts to confirm the theory of the geometric mean plasma emission. This process results from two interpenetrating electron beams in a Penning discharge. Effort were made on diagnostic and software development for the study of plasma turbulence, automatic reduction of Langmuir probe data, and correlation studies of plasma fluctuations and turbulence using digital time series analysis techniques based on the fast Fourier transform. The methods of chaos theory are applied to the investigation of plasma turbulence, using a commercially available software program. Extensive studies were conducted of fluctuations in a highly turbulent Penning discharge. By perturbing the plasma with a signal of known amplitude and frequency applied to an effector probe, one can demonstrate the enhancement of plasma turbulence and the resulting turbulent heating of the plasma electron and/or ion population. These active modification experiments also demonstrated conditions under which a low-frequency modulation of the plasma by the effector probe could dampen the turbulent modes present in the unmodulated plasma. The damping of turbulent modes at higher frequencies, above 50 kilohertz, was as high as 10 to 20 db in some instances. This suggests a way to actively modify plasma turbulence and affect or reduce transport parameters which depend on the level of plasma turbulence. A diagnostic procedure was developed for measuring the effective collision frequency of electrons in plasmas due not only to binary collisions with other electron or neutral atoms, but also to turbulent collisions of the electrons that result when the electrons scatter off fluctuating electric fields.

• Research Organization: Tennessee Univ., Knoxville, TN (USA). Plasma Science Lab.
• OSTI ID: 5593633
• Report Number(s): AD-A-207017/5/XAB; UTK-PSL-89-1
• Country of Publication: United States
• Language: English

Related Subjects

640410* -- Fluid Physics-- General Fluid Dynamics
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ATOMS
BEAMS
CHARGED PARTICLES
COLLISIONS
COMPUTER CODES
DAMPING
DOCUMENT TYPES
ELECTRIC DISCHARGES
ELECTRIC FIELDS
ELECTRIC PROBES
ELECTROMAGNETIC RADIATION
ELECTRON BEAMS
ELECTRONS
ELEMENTARY PARTICLES
EMISSION
EMISSION SPECTRA
FERMIONS
FOURIER TRANSFORMATION
FREQUENCY MODULATION
GEOMETRY
HEATING
INTEGRAL TRANSFORMATIONS
IONS
LANGMUIR PROBE
LEPTON BEAMS
LEPTONS
MATHEMATICS
MODULATION
OPTIMIZATION
PARTICLE BEAMS
PENNING DISCHARGES
PLASMA
PROBES
PROGRESS REPORT
RADIATIONS
RADIOWAVE RADIATION
SPECTRA
TIME-SERIES ANALYSIS
TRANSFORMATIONS