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Manuscript Title: POS - A 1d time-dependent H+ ion source code.
Authors: A.H. Glasser, K. Smith
Program title: POS
Catalogue identifier: ABJU_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 55(1989)409
Programming language: Fortran.
Computer: CRAY.
Operating system: CTSS.
Word size: 60
Peripherals: disc, graph plotter.
Keywords: Ion source, Plasma fluids, Atomic collisions, Plasma physics, Atomic process, Transport.
Classification: 19.1, 19.11.

Nature of problem:
POS is a computer program that predicts the number densities, drift velocities, and electron and ion temperatures of two fluids, e and H+, in a volume ion source, including the effect of a magnetic filter field.

Solution method:
The fundamental equations of the model are the first three velocity moments of the Boltzmann transport equation, as derived by Braginski for two fully ionized fluids, H+ and e. The Braginskii equations have been enhanced by including the effects of chemical reactions, and the transport coefficients have been modified empirically by including the effect of collisions with neutrals. Numerical solutions to the four (plasma density, drift, velocity, electron, and ion temperatures) coupled, time-dependent equations have been obtained using the method of moving finite elements.

The model is restricted to one spatial dimension, the axis of a cylindrical ion source. Consequently, the role of the walls of the device has been neglected. Furthermore, there is no net current, and only the dominant volume collision processes have been included. Because the theory is a two-fluid model, then no account is given of the changes in the variables associated with other species, for example, H, H2,H2*,H2+,H3+,etc.

Running time:
Execution time for the dependent variables to reach a steady state takes typically 2 min on a CRAY-XMP.