Effects of reflections and trapped ions on the thermionic emitter sheath

Conference · Sat Jan 01 04:00:00 EST 1983

OSTI ID:6101343

Main, G L; Lam, S H

The theoretically reducible part of the plasma arc-drop (that which is attributable to plasma resistance) of a thermionic energy converter operating in the ignited mode can ultimately be attributed to the loss of positive ions and plasma electrons to the electrodes. Most experimental converter C-V characteristics exhibit a region with a relatively constant and small value of converter current at the foot of the relatively sharply rising Boltzman region. Little attention has been paid to this region because its output power is usually very small (in spite of the favorable arc-drop values). Occasionally this region is simply dismissed as operating in the diffusion mode without further comment or study. The present paper explores the effects of the reflection and trapping of positive ions at current levels where this low plateau region appears. However, contrary to the experimental results, all analytical calculations performed so far indicate that a consequence of reflection and trapping is an increase in arc-drop. The apparent contradiction between theory and experiment in this low current regime indicate that our theoretical modelling of the converter is not yet complete. Aspects of our theoretical model that might account for this lack of agreement is discussed in later sections.

• Research Organization: Princeton Univ., NJ (USA). Dept. of Mechanical and Aerospace Engineering
• DOE Contract Number: AC02-76ET15352
• OSTI ID: 6101343
• Report Number(s): CONF-830812-1; ON: DE83010233
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
300400* -- Thermionic Converters
BOLTZMANN EQUATION
CATIONS
CHARGED PARTICLES
CURRENT DENSITY
DATA
DIFFERENTIAL EQUATIONS
DIFFUSION
DIRECT ENERGY CONVERTERS
EIGENVALUES
ENERGY LOSSES
EQUATIONS
INFORMATION
ION DRIFT
IONS
LOSSES
NESDPS Office of Nuclear Energy Space and Defense Power Systems
NUMERICAL DATA
PARTIAL DIFFERENTIAL EQUATIONS
PLASMA SHEATH
REFLECTION
THEORETICAL DATA
THERMIONIC CONVERTERS
TRAPPING