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Laser Wakefield Acceleration Using Few-millijoule Laser Pulses at Kilohertz Repetition-Rate.

dc.contributor.authorHe, Zhaohanen_US
dc.date.accessioned2015-01-30T20:11:34Z
dc.date.availableNO_RESTRICTIONen_US
dc.date.available2015-01-30T20:11:34Z
dc.date.issued2014en_US
dc.date.submitteden_US
dc.identifier.urihttps://hdl.handle.net/2027.42/110389
dc.description.abstractCompared to conventional sources, electrons produced by a laser plasma based accelerator have some unique properties owing to the much higher acceleration gradient that can be sustained in plasma and the inherent synchronization with the driving laser pulse, making them a potentially useful source for developing tools for ultrafast time-resolved studies. This past decade has seen significant advances in the field of laser driven plasma accelerators, which can now generate electron beams with few femtosecond durations and up to GeV energies. One of the main issues with plasma accelerators has been their shot-to-shot reproducibility and stability. In addition, experiments to date have been carried out at low-repetition rate. For many potential applications, increasing the repetition rate from a few hertz to kilohertz or higher will be required. This thesis describes both experimental and numerical work aiming at the development of a wakefield electron source and applications at kilohertz repetition-rate using few-millijoule pulses. We first present a simple yet robust optical pulse compression technique utilizing ionization nonlinearity. A self-compressed 16 fs pulse was measured from an original 36 fs pulse containing a few millijoules of energy, which can be beneficial for driving laser wakefield acceleration. Electron acceleration using uncompressed multi-millijoule laser pulses (8 mJ, 32 fs) was studied both in experiments and with particle-in-cell simulations. The wakefield acceleration experiments described in this thesis are the first of their kind at kHz repetition rate and the first to use a relatively low peak-power (0.3 TW) laser system. Generation of sub-relativistic electron beams from laser wakefield acceleration was demonstrated using this high-repetition rate system. An adaptive optimization method was implemented to improve the performance of laser wakefield acceleration through coherent manipulation of the wavefront of the driving laser pulse, enabled by the stability and high-repetition rate. The structure and dynamics of the plasma wave can be subsequently controlled, leading to more than one order of magnitude improvement on the total beam charge and divergence. Finally, the feasibility of using wakefield electrons for ultrafast studies was investigated through proof-of-principle electron diffraction experiments and probing the ultrafast dynamics of a non-equilibrium laser produced plasma.en_US
dc.language.isoen_USen_US
dc.subjectlaser wakefield accelerationen_US
dc.subjectplasma acceleratoren_US
dc.subjectpulse compressionen_US
dc.subjectelectron sourceen_US
dc.subjectadaptive opticsen_US
dc.subjectultrafast scienceen_US
dc.titleLaser Wakefield Acceleration Using Few-millijoule Laser Pulses at Kilohertz Repetition-Rate.en_US
dc.typeThesisen_US
dc.description.thesisdegreenamePhDen_US
dc.description.thesisdegreedisciplineNuclear Engineering and Radiological Sciencesen_US
dc.description.thesisdegreegrantorUniversity of Michigan, Horace H. Rackham School of Graduate Studiesen_US
dc.contributor.committeememberThomas, Alexander George Royen_US
dc.contributor.committeememberGalvanauskas, Almantasen_US
dc.contributor.committeememberKrushelnick, Karl M.en_US
dc.contributor.committeememberNees, John A.en_US
dc.contributor.committeememberClarke, Royen_US
dc.subject.hlbsecondlevelScience (General)en_US
dc.subject.hlbtoplevelEngineeringen_US
dc.subject.hlbtoplevelScienceen_US
dc.description.bitstreamurlhttp://deepblue.lib.umich.edu/bitstream/2027.42/110389/1/zhhe_1.pdf
dc.owningcollnameDissertations and Theses (Ph.D. and Master's)


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