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An experimental investigation of hollow cathode-based plasma contactors. ph.d. thesis
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Williams, John D. |
| Copyright Year | 1991 |
| Description | Experimental results are presented which describe operation of the plasma environment associated with a hollow cathod-based plasma contactor collecting electrons from or emitting them to an ambient, low density Maxwellian plasma. A one-dimensional, phenomenological model of the near-field electron collection process, which was formulated from experimental observations, is presented. It considers three regions, namely, a plasma cloud adjacent to the contactor, an ambient plasma from which electrons are collected, and a double layer region that develops between the contactor plasma cloud and the ambient plasma regions. Results of the electron emission experiments are also presented. An important observation is made using a retarding potential analyzer (RPA) which shows that high energy ions generally stream from a contactor along with the electrons being emitted. A mechanism for this phenomenon is presented and it involves a high rate of ionization induced between electrons and atoms flowing together from the hollow cathode orifice. This can result in the development of a region of high positive potential. Langmuir and RPA probe data suggest that both electrons and ions expand spherically from this hill region. In addition to experimental observations, a one-dimensional model which describes the electron emission process and predicts the phenomena just mentioned is presented and shown to agree qualitatively with these observations. |
| File Size | 3637066 |
| Page Count | 124 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19910016529 |
| Archival Resource Key | ark:/13960/t46q6vs4v |
| Language | English |
| Publisher Date | 1991-05-01 |
| Access Restriction | Open |
| Subject Keyword | Plasma Physics Earth Orbital Environments Plasma Generators Hollow Cathodes Plasma Potentials Spacecraft Charging Plasma Clouds Space Charge Tethering Models Plasma Currents Electron Emission Space Plasmas Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Thesis |
