Undergraduate Honors Theses

Author

Jia HanFollow

Thesis Defended

Spring 2017

Document Type

Thesis

Type of Thesis

Departmental Honors

Department

Physics

First Advisor

Tobin Munsat

Abstract

We perform laboratory experiments on the Colorado Solar Wind Experiment (CSWE) device to study the dynamics of the solar wind interaction with lunar magnetic anomalies. A large cross- section plasma ow with ion energies between 100 and 800 eV is incident on an insulating surface embedded in a magnetic dipole field. Plasma is created by a Kaufman ion source. The beam profile has been characterized using a Langmuir probe and an ion Energy Analyzer. The dipole field is created with a permanent magnet behind the surface. 2D potential profiles are measured above the surface using an emissive Langmuir probe. With a dipole moment perpendicular to the surface, the results show large positive potentials on the surface in the dipole lobe regions, where the electrons are magnetically shielded while the unmagnetized ions go to the surface. However, the magnitudes of these positive potentials follow the ion energies (in eV) until 200 eV. Three possible explanations are investigated, including: (i) the electric field model, (ii) secondary electron emission, (iii) surface material effect. This laboratory study will enhance our knowledge on the lunar electric environment in the magnetic anomaly regions, which will help us to understand the formation of the high-albedo swirl-shaped markers on the lunar surface.

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