Date of Award

12-2014

Document Type

Thesis - Open Access

Degree Name

Master of Science in Engineering Physics

Department

Physical Sciences

Committee Chair

Dr. Aroh Barjatya

First Committee Member

Dr. Charles Lee

Second Committee Member

Dr. Bereket Berhane

Abstract

The Langmuir probe technique is the predominant in-situ plasma diagnostic technique, and is arguably the only measurement technique that is universally own on every sounding rocket investigation. Earth's mesosphere region (80-120 km) is a host of many dynamic phenomena such as the noctilucent clouds, breaking gravity waves, inversion layers, settlement of mesospheric smoke particles, etc. As such it is critical to have a comprehensive suite of plasma diagnostics that can unambiguously measure various plasma parameters.

This thesis deals with the development and testing of three different Langmuir probe implementations suitable for investigation of the mesosphere which are to be launched as part of the Mesosphere Turbulence Experiment sounding rockets. Two of the implementations are fixed bias Langmuir probes with different probe geometries, and the third implementation is a typical cylindrical sweeping Langmuir probe.

Amongst the fixed bias Langmuir probe implementations, the multi-needle fixed bias Langmuir probe is a collection of three fixed bias needles at distinct voltages in the electron saturation region that can together make an absolute electron density measurement that is immune to low levels of spacecraft charging. Similarly, the multi-surface fixed bias Langmuir probe is a collection of three spherical probes, however these are biased at the same potential in the electron saturation region while each having a different metal electroplated on its surface. This probe not only gives relative plasma density measurements, but is also able to detect the presence of mesospheric smoke particles. The sweeping Langmuir probe is a traditional Langmuir probe implementation capable of giving us absolute density and electron temperature along with payload floating potential.

The work towards this thesis involved the design of these various implementations in National Instrument's Multisim, the layout of the boards in National Instrument's Ultiboard, the board population, calibration and testing. Finally, the sweeping Lang-Muir probe electronics were also tested in the new ERAU Space Plasma Chamber.

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