Collisionless ion collection by non-emitting spherical bodies in E x B fields

The three-dimensional interaction of a magnetized, collisionless flowing plasma with a non-emitting conducting sphere is solved in the entire range of physically allowed parameters, in the ion-collecting regime. This can be considered as the "spherical Mach probe" problem, establishing how the ion flux to the surface varies with orientation and external velocity; the study is however of broader interest, as the sphere can also be seen as a dust particle or any ionospheric body. The core tool developed for this study is the fully parallelized (particle + field solver) Particle-In-Cell code SCEPTIC3D, three-dimensional evolution of SCEPTIC, accounting for the full ion distribution function and Boltzmann electrons. Investigations are first carried out in the quasineutral limit. Results include a report of ion current dependence on the external plasma parameters, as well as a theoretical calibration for transverse Mach probes with four electrodes oriented at 450 to the magnetic field in a plane of flow and magnetic field, valid for arbitrary temperature and ion magnetization. The analysis is preceded by an independent semi-analytic treatment of strongly magnetized ion collection by oblique surfaces, successfully validating SCEPTIC3D's behaviour.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Nuclear Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2010

Author dc:creator

• Patacchini, Leonardo

Advisor dc:contributor.advisor

• Ian H. Hutchinson.

• Nuclear Science and Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/57989

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/57989