Faculty Advisor or Committee Member

Nikolaos A. Gatsonis, Advisor

Faculty Advisor or Committee Member

Michael Demetriou, Committee Member

Faculty Advisor or Committee Member

John Blandino, Committee Member

Faculty Advisor or Committee Member

William Durgin, Committee Member

Co-advisor

David Cooke

Identifier

etd-051006-112304

Abstract

The Turning Point Method (TPM) for the evaluation of ion scattering in a sheath of a biased probe immersed in an unmagnetized plasma is reviewed. The TPM implemented originally in a computer program for spherical probes is expanded to include cylindrical probes as well as the evaluation of the turning angle of the charged particle (repelled or attracted) around the probe. TPM results have the potential to provide a standard against which to compare more complicated current collection simulations. TPM results are validated by comparing with Laframboise's earlier work for current collection in the Orbital Motion Limited regime. Calculations of the turning angle of a charged particle with specific energy and angular momentum revealed that higher plasma shielding limits the range of impact parameters that experience significant scattering, and that attracted particles entering tangent to the sheath experience increased scattering. The TPM results also show that there are significant changes in orbital trajectories between different space charges within the Orbital Motion Limited limit.

Publisher

Worcester Polytechnic Institute

Degree Name

MS

Department

Mechanical Engineering

Project Type

Thesis

Date Accepted

2006-05-10

Accessibility

Unrestricted

Subjects

orbital trajectory, ion collection, turning point method, spherical probes, turning angle, ion scattering, cylindrical probes, Ions, Scattering, Probes (Electronic instruments), Orbital mechanics, Space plasmas

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