Laser Wakefield and Direct Acceleration in the Plasma Bubble Regime - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Laser Wakefield and Direct Acceleration in the Plasma Bubble Regime write by Zhang, Xi (Ph. D.). This book was released on 2017. Laser Wakefield and Direct Acceleration in the Plasma Bubble Regime available in PDF, EPUB and Kindle. Laser wakefield acceleration (LWFA) and direct laser acceleration (DLA) are two different kinds of laser plasma electron acceleration mechanisms. LWFA relies on the laser-driven plasma wave to accelerate electrons. The interaction of ultra-short ultra-intensive laser pulses with underdense plasma leads the LWFA into a highly nonlinear regime (“plasma bubble regime”) that attracts particular interest nowadays. DLA accelerates electrons by laser electromagnetic wave in the ion channel or the plasma bubble through the Betatron resonance. This dissertation presents a hybrid laser plasma electron acceleration mechanism. We investigate its features through particle-in-cell (PIC) simulations and the single particle model. The hybrid laser plasma electron acceleration is the merging concept between the LWFA and the DLA, so called laser wakefield and direct acceleration (LWDA). The requirements of the initial conditions of the electron to undergo the LWDA are determined. The electron must have a large initial transverse energy. Two electron injection mechanisms that are suitable for the LWDA, density bump injection and ionization induced injection, are studied in detail. The features of electron beam phase space and electron dynamics are explored. Electron beam phase space appears several unique features such as spatially separated two groups, the correlation between the transverse energy and the relativistic factor and the double-peak spectrum. Electrons are synergistically accelerated by the wakefield as well as by the laser electromagnetic field in the laser-driven plasma bubble. LWDA are also investigated in the moderate power regime (10 TW) in regarding the effects of laser color and polarization. It is found that the frequency upshift laser pulse has better performance on avoiding time-jitter of electron energy spectra, electron final energy and electron charge yield. Some basic characters that related to the LWDA such as the effects of the subluminal laser wave, the effects of the longitudinal accelerating field, the electron beam emittance, the electron charge yield and potentially applications as radiation source are discussed.
Supra-bubble Regime for Laser Acceleration of Coldelectron Beams in Tenuous Plasma
Supra-bubble Regime for Laser Acceleration of Coldelectron Beams in Tenuous Plasma - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Supra-bubble Regime for Laser Acceleration of Coldelectron Beams in Tenuous Plasma write by . This book was released on 2009. Supra-bubble Regime for Laser Acceleration of Coldelectron Beams in Tenuous Plasma available in PDF, EPUB and Kindle. Relativistic electrons can be accelerated by an ultraintense laser pulse in the "supra-bubble" regime, that is, in the blow-out regime ahead of the plasma bubble (as opposed to the conventional method, when particles remain inside the bubble). The acceleration is caused by the ponderomotive force of the pulse, via the so-called snow-plow mechanism. The maximum energy gain, [Delta][gamma] ~ [gamma]g a, is attained when the particle Lorentz factor [gamma] is initially about [gamma]g/a, where [gamma]g is the pulse group speed Lorentz factor, and a is the laser parameter, proportional to the laser field amplitude. The scheme operates at a ≤ [gamma]g, yielding [Delta][gamma] of up to that via wakefield acceleration for the same plasma and laser parameters, [Delta][gamma] ~ [gamma]2g. The interaction length is shorter than that for the wake field mechanism but grows with the particle energy, hindering acceleration in multiple stages.
Direct Laser Acceleration in Laser Wakefield Accelerators
Direct Laser Acceleration in Laser Wakefield Accelerators - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Direct Laser Acceleration in Laser Wakefield Accelerators write by Jessica Shaw. This book was released on 2016. Direct Laser Acceleration in Laser Wakefield Accelerators available in PDF, EPUB and Kindle. In this dissertation, the direct laser acceleration (DLA) of ionization-injected electrons in a laser wakefield accelerator (LWFA) operating in the quasi-blowout regime has been investigated through experiment and simulation. In the blowout regime of LWFA, the radiation pressure of an intense laser pulse can push a majority of the plasma electrons out and around the main body of the pulse. The expelled plasma electrons feel the electrostatic field of the relatively-stationary ions and are thus attracted back towards the laser axis behind the laser pulse where they overshoot the axis and set up a wake oscillation. When ionization injection is used, the inner-shell electrons of higher-Z dopant atoms are tunnel ionized near the peak of the laser pulse. Those electrons slip back relative to the wake until they gain enough energy from the longitudinal wakefield to become trapped. Those electrons that are trapped off-axis will undergo betatron oscillations in response to the linear transverse focusing force of the ions. Through experiments and supporting simulations, this dissertation demonstrates that when there is a significant overlap between the drive laser and the trapped electrons in a LWFA cavity, the accelerating electrons can gain energy from the DLA mechanism in addition to LWFA. When laser pulse overlaps the trapped electrons, the betatron oscillations of the electrons in the plane of the laser polarization can lead to an energy transfer from the transverse electric field of the laser to the transverse momentum of the electrons. This enhanced transverse momentum can then be converted into increased longitudinal momentum via the v x B force of the laser. This process is known as DLA. In this experimental work, the properties of the electron beams produced in a LWFA where the electrons are injected by ionization injection and become trapped without escaping the laser field have been investigated. The maximum measured energy of the produced electron beams scales with the overlap between the electrons and the laser. Undispersed electrons beams are observed to be elliptical in the plane of the laser polarization, and the energy spectrum splits into a fork at higher energies when the electrons beams are dispersed orthogonal to the direction of the laser polarization. These characteristic features are reproduced in particle-in-cell (PIC) code simulations where particle tracking was used to demonstrate that such spectral features are signatures of the presence of DLA in LWFA. Further PIC simulations comparing LWFA with and without DLA show that the presence of DLA can lead to electron beams that have maximum energies that exceed the estimates given by the theory for the ideal blowout regime. The magnitude of the contribution of DLA to the energy gained by the electron was found to be on the order of the LWFA contribution. In the LWFAs studied here, both DLA and LWFA participate in accelerating the bulk of the electrons in the produced electron beam. The presence of DLA in a LWFA can also lead to enhanced betatron oscillation amplitudes and increased divergence in the direction of the laser polarization.
Phase Space Dynamics in Plasma Based Wakefield Acceleration
Phase Space Dynamics in Plasma Based Wakefield Acceleration - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Phase Space Dynamics in Plasma Based Wakefield Acceleration write by Xinlu Xu. This book was released on 2020-01-02. Phase Space Dynamics in Plasma Based Wakefield Acceleration available in PDF, EPUB and Kindle. This book explores several key issues in beam phase space dynamics in plasma-based wakefield accelerators. It reveals the phase space dynamics of ionization-based injection methods by identifying two key phase mixing processes. Subsequently, the book proposes a two-color laser ionization injection scheme for generating high-quality beams, and assesses it using particle-in-cell (PIC) simulations. To eliminate emittance growth when the beam propagates between plasma accelerators and traditional accelerator components, a method using longitudinally tailored plasma structures as phase space matching components is proposed. Based on the aspects above, a preliminary design study on X-ray free-electron lasers driven by plasma accelerators is presented. Lastly, an important type of numerical noise—the numerical Cherenkov instabilities in particle-in-cell codes—is systematically studied.
Plasma Streaming Instabilities in the Laser Wakefield Acceleration Bubble
Plasma Streaming Instabilities in the Laser Wakefield Acceleration Bubble - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Plasma Streaming Instabilities in the Laser Wakefield Acceleration Bubble write by Lucas Ivan Iñigo Gamiz. This book was released on 2022. Plasma Streaming Instabilities in the Laser Wakefield Acceleration Bubble available in PDF, EPUB and Kindle.
