Author: Grace Gloria ManahanPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Studies of Transverse Properties of Relativistic Electrons from Laser Wakefield Accelerator
Author: Grace Gloria ManahanStudy of Relativistic Electrons Generated from Ultra-intense Laser-plasma Interaction Relevant to Laser Wakefield Acceleration and Fast Ignition Laser Fusion
Author: Mianzhen MoPublisher:
ISBN:
Category : Electrons
Languages : en
Pages : 283
Book Description
Ultra-intense (> 10^18 W/cm^2) laser interaction with matter is capable of producing relativistic electrons which have a variety of applications in scientific and medical research. Knowledge of various aspects of these hot electrons is important in harnessing them for various applications. Of particular interest for this thesis is the investigation of hot electrons generated in the areas of Laser Wakefield Acceleration (LWFA) and Fast Ignition (FI). LWFA is a physical process in which electrons are accelerated by the strong longitudinal electrostatic fields that are formed inside the plasma cavities or wakes produced by the propagation of an ultra-intense laser pulse through an under-dense plasma. The accelerating E-fields inside the cavities are 1000 times higher than those of conventional particle accelerators and can accelerate electrons to the relativistic regime in a very short distance, on the order of a few millimeters. In addition, Betatron X-ray radiation can be produced from LWFA as a result of the transverse oscillations of the relativistic electrons inside the laser wakefield driven cavity. The pulse duration of Betatron radiation can be as short as a few femtoseconds, making it an ideal probe for measuring physical phenomena taking place on the time scale of femtoseconds. Experimental research on the electron acceleration of the LWFA has been conducted in this thesis and has led to the generation of mono-energetic electron bunches with peak energies ranging from a few hundreds of MeV to 1 GeV. In addition, the Betatron radiation emitted from LWFA was successfully characterized based on a technique of reflection off a grazing incidence mirror. Furthermore, we have developed a Betatron X-ray probe beamline based on the technique of K-shell absorption spectroscopy to directly measure the temporal evolution of the ionization states of warm dense aluminum. With this, we have achieved for the first time direct measurements of the ionization states of warm dense aluminum using Betatron X-ray radiation probing. Fast Ignition (FI) is an advanced scheme for inertial confinement fusion (ICF), in which the fuel ignition process is decoupled from its compression. Comparing with the conventional central hot-spot scheme for ICF, FI has the advantages of lower ignition threshold and higher gain. The success of FI relies on efficient energy coupling from the heating laser pulse to the hot electrons and subsequent transport of their energy to the compressed fuel. As a secondary part of this thesis, the transport of hot electrons in overdense plasma relevant to FI was studied. In particular, the effect of resistive layers within the target on the hot electron divergence and absorption was investigated. Experimental measurements were carried out and compared to simulations indicating minimal effect on the beam divergence but some attenuation through higher atomic number intermediate layers was observed.
Relativistic Electron-cyclotron Resonances in Laser Wakefield Acceleration
Author: Matthew SchwabPublisher:
ISBN:
Category :
Languages : de
Pages : 0
Book Description
In this thesis, the magnetized, relativistic plasma that overlaps the pump laser in Laser Wakefield Acceleration (LWFA) was investigated. The Jeti 40 laser was used to drive the plasma wave and a transverse, few-cycle probe pulse in the visible to near-infrared spectrum was implemented to image the laser-plasma interaction. The recorded shadowgrams were sorted depending on the properties of the accelerated electron bunches, and subsequently stitched together based on the timing delay between the pump and probe beams. The resulting data showed two signatures unique to the relativistic, magnetized plasma near the pump pulse. Firstly, a significant change in the brightness modulation of the shadowgrams, coinciding with the location of the pump pulse, shows a strong dependence on the pump's propagation length and the probe's spectrum and polarization. Secondly, after ~1.5 mm of propagation in the plasma, polarization-dependent diffraction rings appear in front of the plasma wave. A mathematical model using relativistic corrections to the Appleton-Hartree equation was developed to explain these signals. By combining the model with data from 2D Particle-in-Cell (PIC) simulations using the VSim code, the plasma's birefringent refractive index distribution was investigated. Simulated shadowgrams of a 3D PIC simulation using the EPOCH code were also analyzed with respect to the aforementioned signals. The results of the study present a compelling description of the pump-plasma interaction. The previously unknown signals arise from relativistic, electron-cyclotron motion originating in the 10s of kilotesla strong magnetic fields of the pump pulse. Advantageously, a VIS-NIR probe is resonant with the cyclotron frequencies at the peak of the pump. With further refinement, the measurement of this phenomenon could allow for the non-invasive experimental visualization of the pump laser's spatio-temporal energy distribution and evolution during propagation through the plasma.
Progress in Ultrafast Intense Laser Science XVII
Author: Kaoru YamanouchiPublisher: Springer Nature
ISBN: 3031554639
Category : Laser pulses, Ultrashort
Languages : en
Pages : 227
Book Description
This book covers a broad range of interdisciplinary topics, focusing on atoms and molecules in intense laser fields, excitation processes in intense laser fields, photonics and materials, high-order harmonics generation, XFEL, high-power lasers and their applications, and quantum computing. This seventeenth volume features contributions from world-renowned researchers on topics such as applications of attosecond and femtosecond laser pulses, coherence and dynamics in quantum systems, and applications of super-intense laser fields. The PUILS series delivers up-to-date reviews of progress in this emerging interdisciplinary research field, spanning atomic and molecular physics, molecular science, and optical science, which has been stimulated by the recent developments in ultrafast laser technologies. Each volume compiles peer-reviewed articles authored by researchers at the forefront of each of their own subfields of ultrafast intense laser science. Every chapter opens with an overview of the topics to be discussed, so that researchers unfamiliar with the subfield, especially graduate students, can grasp the importance and attractions of the research topic at hand; these are followed by reports of cutting-edge discoveries.
Laser-plasma Interactions Used for the Acceleration of Electrons
Author: Evan Stuart DoddScientific and Technical Aerospace Reports
Author: Reviews Of Accelerator Science And Technology - Volume 9: Technology And Applications Of Advanced Accelerator Concepts
Author: Alexander Wu ChaoPublisher: World Scientific
ISBN: 9813209593
Category : Science
Languages : en
Pages : 344
Book Description
Since its invention in the 1920s, particle accelerators have made tremendous progress in accelerator science, technology and applications. However, the fundamental acceleration principle, namely, to apply an external radiofrequency (RF) electric field to accelerate charged particles, remains unchanged. As this method (either room temperature RF or superconducting RF) is approaching its intrinsic limitation in acceleration gradient (measured in MeV/m), it becomes apparent that new methods with much higher acceleration gradient (measured in GeV/m) must be found for future very high energy accelerators as well as future compact (table-top or room-size) accelerators. This volume introduces a number of advanced accelerator concepts (AAC) — their principles, technologies and potential applications. For the time being, none of them stands out as a definitive direction in which to go. But these novel ideas are in hot pursuit and look promising. Furthermore, some AAC requires a high power laser system. This has the implication of bringing two different communities — accelerator and laser — to join forces and work together. It will have profound impact on the future of our field.Also included are two special articles, one on 'Particle Accelerators in China' which gives a comprehensive overview of the rapidly growing accelerator community in China. The other features the person-of-the-issue who was well-known nuclear physicist Jerome Lewis Duggan, a pioneer and founder of a huge community of industrial and medical accelerators in the US.
Phase Space Dynamics in Plasma Based Wakefield Acceleration
Author: Xinlu XuPublisher: Springer Nature
ISBN: 9811523819
Category : Science
Languages : en
Pages : 138
Book Description
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.
Advanced Accelerator Concepts
Author: Manoel CondePublisher: American Institute of Physics
ISBN: 9780735403789
Category : Science
Languages : en
Pages : 954
Book Description
This workshop covered the general field of advanced particle accelerators, exploring the science and technology of a multitude of novel acceleration schemes. Various schemes under study utilize combinations of plasmas, laser beams, dielectric materials, and RF power. The development of technologies that will enable the design of future high energy physics machines is the underlying goal of this workshop.
Free Electron Laser Instability for a Relativistic Solid Electron Beam in a Helical Wiggler Field
Author: Han S. UhmPublisher:
ISBN:
Category :
Languages : en
Pages : 70
Book Description
The free electron laser instability for a solid relativistic electron beam propagating in combined transverse helical wiggler and uniform axial guide fields is investigated within the framework of the linearized Vlasov-Maxwell equations. Stability properties are investigated for the choice of equalibrium distribution function in which all electrons have the same value of the linear combination of transverse and helical invariants. The instability growth rate is calculated including a determination of the optimum value of the ratio of beam radius to conducting wall radius for maximum growth. It is found that the maximum growth rate for a solid electron beam is comparable to that for a hollow beam with similar parameters. Moreover, the introduction of a small axial momentum spread significantly reduces the instability growth rate.