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.

Creator

• Figueroa, Shana Suzanne

Contributors

• Demetriou, Michael A.
• Gatsonis, Nikolaos A.
• Durgin, William W.
• Blandino, John J.

Degree

• MS

Unit

• Mechanical Engineering

Publisher

• Worcester Polytechnic Institute

Language

• English

Identifier

• etd-051006-112304

Keyword

• turning point method
• spherical probes
• cylindrical probes
• orbital trajectory
• ion scattering
• ion collection
• turning angle

Advisor

• Gatsonis, Nikolaos A.

Committee

• Demetriou, Michael A.
• Blandino, John
• Durgin, William W.

Defense date

• 2006-05-08

Year

• 2006

Date created

• 2006-05-10

Resource type

• Thesis

Rights statement

• In Copyright

Last modified

• 2023-08-10