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Title: Computer modeling of linear theta pinch machines

Journal Article · · Phys. Fluids; (United States)
DOI:https://doi.org/10.1063/1.862116· OSTI ID:6635836

A zero-dimensional time dependent computer model is developed to describe post implosion behavior of a radially diffuse plasma column in linear theta pinch machines. The model consists of five first-order differential equations for electron temperature T/sub e/, ion temperature T/sub i/, plasma column area A/sub p/, magnetic field embedded in the plasma column B/sub i/, and number of electrons in the plasma column N, and incorporates the effects of particle end loss, electron and ion thermal conduction, magnetic compression of the plasma, electron-ion energy transfer, Ohmic heating of the electrons, and magnetic field diffusion. End-on interferometric experimental data, which indicate that particle confinement time scales as L(m/sub i//(T/sub e/+T/sub i/))/sup 1/2/, where m/sub i/ is the ion mass and L is the compression coil length, are used as a guide to the choice of an end loss parameter. Numerical predictions of on-axis density and plasma temperature are found to be in reasonably good agreement with experimental results from both the collisional Scylla I-C experiment and the hot collisionless Scylla IV-P experiment. These comparisons are used to identify important physical mechanisms characterizing the behavior of a particular machine including: the significance of thermal conduction on both plasma temperature and particle end loss; the importance of magnetic field diffusion; and the impact of using a time independent end loss scaling parameter.

Research Organization:
The Pennsylvania State University, University Park, Pennsylvania 16802
OSTI ID:
6635836
Journal Information:
Phys. Fluids; (United States), Vol. 21:11
Country of Publication:
United States
Language:
English