Physics and applications of a plasma deflagration accelerator
Abstract/Contents
- Abstract
- Pulsed, gas-fed plasma accelerators are known to operate in a mode that is characterized by ultra-high velocity, collimated plasma jets known as a ``plasma deflagration.'' Despite a degree of continuous scientific attention over several decades, both the basic underlying physics and the complex dynamics that contribute to the formation and evolution of these jets remains poorly understood. The high energy densities and inherently transient nature of these pulsed systems make for a challenging diagnostic environment, and offer an array of both physical questions and potential applications that are the focus of this dissertation. This work concerns the experimental investigation of several aspects of a pulsed plasma accelerator operated in the deflagration mode. Particular focus is given to physics governing the formation and subsequent behavior of the collimated outflowing jet, whereas prior studies have primarily engaged with the acceleration process in the inter-electrode region of the plasma gun. Three main diagnostics were implemented and are discussed, each with the aim of characterizing a specific feature of the plasma accelerator. First, an immersed probe was used to simultaneously measure multiple magnetohydrodynamic (MHD) and thermodynamic state variables at a single point in the plasma flow in order to experimentally test the MHD Rankine-Hugoniot model for plasma deflagrations and detonations. Spectroscopic methods were then applied to quantify the plasma density distribution in the near-field of the accelerator plume, using a high-resolution imaging spectrometer to spatially and spectrally resolve a transaxial slice of the plasma emission from the jet. A radial density profile was computed from the spatial variation of the observed spectral line broadening. A laser schlieren imaging apparatus was then developed, and combined with a high speed camera to capture the evolution of the plasma density structure within the jet during the entire discharge period. Finally, various applications of the deflagration-produced plasma jets were considered, including space propulsion, plasma-material interactions, and laboratory astrophysics. All three of the developed diagnostics were used, alone and in combination, to characterize the deflagration accelerator as applied to these areas. This work represents a comprehensive investigation of the detailed physics of a complex and practically useful plasma accelerator, and improves our theoretical understanding of its operation and performance.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2017 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Loebner, Keith T. K |
|---|---|
| Associated with | Stanford University, Department of Mechanical Engineering. |
| Primary advisor | Cappelli, Mark A. (Mark Antony) |
| Thesis advisor | Cappelli, Mark A. (Mark Antony) |
| Thesis advisor | Edwards, C. F. (Christopher Francis) |
| Thesis advisor | Poehlmann, Flavio |
| Advisor | Edwards, C. F. (Christopher Francis) |
| Advisor | Poehlmann, Flavio |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Keith T. K. Loebner. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2017. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2017 by Keith Thomas Kessler Loebner
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
Also listed in
Loading usage metrics...