Experimental Studies of Spacecraft Plasma Interactions: Facility Characterization and Initial Measurements

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dc.contributor.authorSawyer, Samuel Thomasen
dc.contributor.committeechairWang, Joseph J.en
dc.contributor.committeememberShinpaugh, Kevin A.en
dc.contributor.committeememberScales, Wayne A.en
dc.contributor.departmentAerospace and Ocean Engineeringen
dc.date.accessioned2014-03-14T20:40:25Zen
dc.date.adate2009-07-07en
dc.date.available2014-03-14T20:40:25Zen
dc.date.issued2009-06-09en
dc.date.rdate2012-03-30en
dc.date.sdate2009-06-23en
dc.description.abstractThe objectives of this thesis are to characterize the plasma environment of a new vacuum chamber facility at Virginia Tech and to perform initial measurements of plasma flow field for studying spacecraft-plasma interactions using this facility. An argon plasma environment was created using a hot filament cathode plasma source. Flange plates attached to the sides of the vacuum chamber were modified in order to attach various feedthroughs both now and in the future such that a probe array DAQ system could be used to expedite measurement and analysis. A Langmuir probe array was used to measure 3-D plasma flow field in the chamber. A Matlab code was developed for automatic evaluation of the Langmuir probe traces. Two sets of measurements were preformed. The first measurement characterizes the plasma produced by the hot filament cathode in the chamber. Langmuir Probes were used to characterize the plasma environment yielding the following average characteristics: Plasma Potential = 5.5486V, Electron Saturation Current = 0.003421A, Electron Temperature = 1.505eV, and the Plasma Density = 6.806*10^14 m^-3. It was found that for both the spherical and cylindrical probes used in the test facility Rs > Debye length and thus were analyzed under the thin sheath condition. The second measurement attempts to measure the 3-D plasma flow field for plasma flow over a structure composed of 4-inch biased Al box sitting on a biased Al plate. The results show signs of the the generation of the expansion pre-sheath structure at the leading edge of the plate and the box upper surface predicted by numerical models. However, the current diagnostics system does not have the spatial resolution and range as well as the data accuracy required to reach a definitive measurement of plasma presheath and plasma wake.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-06232009-153026en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-06232009-153026/en
dc.identifier.urihttp://hdl.handle.net/10919/33714en
dc.publisherVirginia Techen
dc.relation.haspartSawyer_Thesis.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectVacuum Chamberen
dc.subjectPlasmaen
dc.subjectLangmuir Probeen
dc.titleExperimental Studies of Spacecraft Plasma Interactions: Facility Characterization and Initial Measurementsen
dc.typeThesisen
thesis.degree.disciplineAerospace and Ocean Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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