Laboratory visualization of laser-driven plasma accelerators in the bubble regime
| dc.contributor.advisor | Downer, Michael Coffin | en |
| dc.contributor.committeeMember | Becker, Michael | en |
| dc.contributor.committeeMember | Ditmire, Todd | en |
| dc.contributor.committeeMember | Lang, Karol | en |
| dc.contributor.committeeMember | Shvets, Gennady | en |
| dc.creator | Dong, Peng | en |
| dc.date.accessioned | 2011-08-01T19:52:55Z | en |
| dc.date.accessioned | 2017-05-11T22:23:01Z | |
| dc.date.available | 2011-08-01T19:52:55Z | en |
| dc.date.available | 2017-05-11T22:23:01Z | |
| dc.date.issued | 2010-08 | en |
| dc.date.submitted | August 2010 | en |
| dc.date.updated | 2011-08-01T19:53:43Z | en |
| dc.description | text | en |
| dc.description.abstract | Accurate single-shot visualization of laser wakefield structures can improve our fundamental understanding of plasma-based accelerators. Previously, frequency domain holography (FDH) was used to visualize weakly nonlinear sinusoidal wakes in plasmas of density n[subscript e] < 0.6 × 10¹⁹/cm³ that produced few or no relativistic electrons. Here, I address the more challenging task of visualizing highly nonlinear wakes in plasmas of density n[subscript e] ~ 1 to 3× 10¹⁹/cm³ that can produce high-quality relativistic electron beams. Nonlinear wakes were driven by 30 TW, 30 fs, 800 nm pump pulses. When bubbles formed, part of a 400 nm, co-propagating, overlapping probe pulse became trapped inside them, creating a light packet of plasma wavelength dimensions--that is, an optical "bullet"--that I reconstruct by FDH methods. As ne increased, the bullets first appeared at 0.8 × 10¹⁹/cm³, the first observation of bubble formation below the electron capture threshold. WAKE simulations confirmed bubble formation without electron capture and the trapping of optical bullets at this density. At n[subscript] >1× 10¹⁹/cm³, bullets appeared with high shot-to-shot stability together with quasi-monoenergetic relativistic electrons. I also directly observed the temporal walk-off of the optical bullet from the beam-loaded plasma bubble revealed by FDH phase shift data, providing unprecedented visualization of the electron injection and beam loading processes. There are five chapters in this thesis. Chapter 1 introduces general laser plasma- based accelerators (LPA). Chapter 2 discusses the FDH imaging technique, including the setup and reconstruction process. In 2006, Dr. N. H. Matlis used FDH to image a linear plasma wakefield. His work is also presented in Chapter 2 but with new analyses. Chapter 3, the main part of the thesis, discusses the visualization of LPAs in the bubble regime. Chapter 4 presents the concept of frequency domain tomography. Chapter 5 suggests future directions for research in FDH. | en |
| dc.description.department | Physics | en |
| dc.format.mimetype | application/pdf | en |
| dc.identifier.slug | 2152/ETD-UT-2010-08-1881 | en |
| dc.identifier.uri | http://hdl.handle.net/2152/ETD-UT-2010-08-1881 | en |
| dc.language.iso | eng | en |
| dc.subject | Lasers | en |
| dc.subject | Plasma accelerators | en |
| dc.subject | Electrons | en |
| dc.subject | Holography | en |
| dc.subject | Laser wakefield structures | en |
| dc.subject | Plasma-based accelerators | en |
| dc.subject | Direct laser acceleration | en |
| dc.subject | Laser-plasma electron acceleration | en |
| dc.subject | Frequency-domain holography | en |
| dc.title | Laboratory visualization of laser-driven plasma accelerators in the bubble regime | en |
| dc.type.genre | thesis | en |