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Full-Text Articles in Physics
Analysis Of Instability Growth And Collisionless Relaxation In Thermionic Converters Using 1-D Pic Simulations, Bret B. Kreh
Analysis Of Instability Growth And Collisionless Relaxation In Thermionic Converters Using 1-D Pic Simulations, Bret B. Kreh
Theses and Dissertations
This work investigates the role that the beam-plasma instability may play in a thermionic converter. The traditional assumption of collisionally dominated relaxation is questioned, and the beam-plasma instability is proposed as a possible dominant relaxation mechanism. Theory is developed to describe the beam-plasma instability in the cold-plasma approximation, and the theory is tested with two common Particle-in- Cell (PIC) simulation codes. The theory is first confirmed using an unbounded plasma PIC simulation employing periodic boundary conditions, ES1. The theoretically predicted growth rates are on the order of the plasma frequencies, and ESl simulations verity these predictions within the order of …
A Three Region Analysis Of A Bounded Plasma Using Particle In Cell And Fluid Techniques, Don F. Nichols
A Three Region Analysis Of A Bounded Plasma Using Particle In Cell And Fluid Techniques, Don F. Nichols
Theses and Dissertations
A detailed collisionless sheath theory and a three-region collisional model of a bounded plasma are presented, and the suitability of the collisional model for analysis of ignited mode thermionic converters is investigated. The sheath theory extends previous analyses to regimes in which the sheath potential and electron temperatures are comparable in magnitude. In all operating regimes typical of a ignited mode thermionic converter, the predicted sheaths extend several mean-free paths. The apparent collisionality of the sheaths prompted development of a collisional, three-region model of the converter plasma. By interfacing Particle-in-Cell regions for the sheaths and fluid regions for the bulk …