Download or read book Optimizing Laser ion Acceleration with Flat and Structured Foils written by Joseph Strehlow and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability of relativistic laser pulses to accelerate ions from foil targets has long been established. These beams, with their high current density and ultrashort duration, are essential tools in high energy density science and have great promise as an upcoming technology in accelerator physics. To best fulfill their applications, the conversion efficiency of laser to ion energy must be optimized, with the ultimate goal of tunable ion energy, yield, and other beam parameters. The acceleration of both light and heavy ions is of interest, as they each have different uses, such as neutron generation and rare isotope production. Two experiments were carried out at the Texas Petawatt laser facility. The first experiment studied the response of imaging plate detectors to heavy ions, expanding the published literature beyond light ion calibrations. Successful modeling of the imaging plate's response function is essential to determining the absolute number of ions accelerated. A comparison of all published calibrations produces an empirical estimate for ion response for any arbitrary ion as a function of atomic mass. The second experiment investigated ion acceleration from 3D printed targets, whose protruding structure increases laser-target coupling. These structures were of the "microtube" geometry, and are most effective under the right conditions of laser intensity, pulse duration, and energy. These results are then compared to experiments on similar target structures at the PHELIX and ALEPH laser facilities, which also showed enhanced ion production. A numerical study on heavy ion acceleration was also conducted, in an optimization of the generation of multiply charged titanium beams. A thickness scan on submicron targets was executed for two laser pulse lengths to determine the best performing target for each laser. In the relativistically induced transparency regime, we show that collisional ionization cannot be neglected for sufficiently long laser pulses (near picosecond). Identifying this threshold is crucial for balancing the conservation of computational resources with accurate particle-in-cell modeling. This large body of experimental and numerical data continue to support the tremendous progress in short pulse laser-ion acceleration over the course of three decades. Continuing to push the bounds in conversion efficiency and beam control is essential for breaking ground in high energy density physics and accelerator development.
Download or read book Optimisation and Control of Ion Acceleration in Intense Laser foil Interactions written by Adam Higginson and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second investigation concerns the diagnosis of the highly transient electric field responsible for ion acceleration in the target normal sheath acceleration (TNSA) regime. High resolution, temporally-resolved measurements of the field evolution are obtained using proton deectometry.
Download or read book Laser Ion Acceleration from a Double layer Metal Foil written by Zsolt Lécz and published by . This book was released on 2013 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optimization of Ion Acceleration from High intensity Laser plasma Interactions written by Hsuan-Gu Chou and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-energy (100s MeV), high spectral quality ion beams are important for many applications like radiography of plasmas, isochoric heating of materials, and tumor therapy. Advances in the development of intense short pulse lasers, recognized with the 2018 Nobel Prize in physics, have been seen as a very promising route to drive compact ion beam sources. However, despite signficant progress over the past two decades, the control of the ion beam properties remains an outstanding challenge. In this Thesis, we discuss two approaches for controlling and optimizing these laser-driven ion beams, using particle-in-cell simulations and theoretical analysis. First, we show that in laser radiation pressure acceleration, the spectral quality of the ion beam is determined by electron heating, which is dictated by the growth of a surface instability. We show that its growth rate imposes an upper limit on the laser pulse duration, and can limit the maximum peak ion beam energy. Next, we explore the development of a hybrid accelerator that combines the advantages of laser-driven beams (compact, high-charge, 10s MeV) with high-gradient RF acceleration in a meter-scale linac, eliminating the large and expensive radio frequency quadrupoles for bunching. Our one-to-one simulations show that the space-charge field plays a critical role in the acceleration effectiveness, and that by tuning the distance at which the laser-driven beam enters the RF, the space-charge field can be controlled such that it actually increases the beam capture. These are important in guiding future experimental developments, for example for the ultrashort laser pulses at state-of-the-art laser facilities and high-gradient linacs, for which we showcase the possibility of a compact (4.5 m) hybrid accelerator that produces a high-quality, high-charge 250 MeV proton beam.
Download or read book Laser Ion Acceleration in Thin Foil Target written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ion Acceleration in Ultra thin Foils Undergoing Relativistically Induced Transparency written by Haydn W. Powell and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis reports on experimental and numerical investigations of ion acceleration and the underlying mechanisms of energy transfer in the interaction of intense laser pulses with ultra-thin foils undergoing relativistic induced transparency. The optimisation and optical control of the ion beam properties including the beam flux, maximum energy and energy spread is important for the development of applications of laser-driven ion beams. Multiple laser-ion acceleration mechanisms, driven by sheath fields, radiation pressure and transparency enhancement occur in intense laser pulse interactions with an ultra-thin foil. This is experimentally and numerically demonstrated in the work presented in this thesis. Results from an experimental investigation of ion acceleration from ultra-thin (nanometer-thick) foils using the Vulcan petawatt laser facility are presented. Spatially separating the multiple beam components arising from the differing acceleration mechanisms enables the underlying physics of the individual mechanisms to be investigated. In the case of foils undergoing relativistic induced transparency, it is shown that an extended channel and resulting jet is formed in the expanding plasma at the rear of the target, resulting in higher laser energy absorption into electrons and enhanced ion acceleration in a localised region. This results from volumetric heating of electrons by the laser pulse propagating within the channel. The measured maximum energy of the protons in the enhanced region of the jet is found to be highly sensitive to the laser pulse contrast and rising edge intensity profile of the laser. It is shown, using a controlled pre-expansion of the target, that an increase in the maximum proton energy by a factor two is achievable. Numerical investigations of the interaction, using particle-in-cell (PIC) simulations, show that an idealised sharp rising edge Gaussian laser intensity profile produces the highest proton energy, though this condition could not be achieved experimentally. The simulations show that controlled pre-expansion of the target, by variation of the rising edge intensity profile, enables better conditions for channel formation and energy coupling to electrons and thus protons. A detailed numerical (PIC) investigation of the mechanisms of laser energy transfer to electrons and ions in thin foils undergoing relativistically induced transparency is also presented. The role of streaming instabilities in the transfer of energy between particle species is investigated. It is found that in addition to the relativistic Buneman instability, which arises from streaming of the volumetrically heated relativistic electrons with the background ions during transparency, ionion streaming in the expanding plasma also plays a role in enhancing the final ion energy. Enhancement of proton maximum energies via ion-ion streaming from shock-accelerated aluminium ions is observed in 1D PIC simulations and the energy exchange is demonstrated to be sensitive to the plasma density. Energy transfer between co-directional ion species is also observed in higher dimension 2D simulations. The simulations show that the greatest enhancement in proton energy is due to streaming of electrons in the region of the plasma jet formed in the expanding plasma.
Download or read book Target and Laser Pulse Optimization for Laser driven Ion Acceleration written by Alexander Permogorov and published by . This book was released on 2021 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Laser driven ION Acceleration written by David C. Carroll and published by . This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Laser Ion Acceleration from Ultrathin Foils and Application to Radiobiology written by Fiona May Hanton and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Laser Ion Acceleration from Ultrathin Foils and Application to Radiobiology written by Fiona Hanton and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Laser Ion Acceleration from the Interaction of Ultra Intense Laser Pulse with Thi Foils written by and published by . This book was released on 2004 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: The discovery that ultra-intense laser pulses (I> 1018 W/cm2) can produce short pulse, high energy proton beams has renewed interest in the fundamental mechanisms that govern particle acceleration from laser-solid interactions. Experiments have shown that protons present as hydrocarbon contaminants on laser targets can be accelerated up to energies> 50 MeV. Different theoretical models that explain the observed results have been proposed. One model describes a front-surface acceleration mechanism based on the ponderomotive potential of the laser pulse. At high intensities (I> 1018 W/cm2), the quiver energy of an electron oscillating in the electric field of the laser pulse exceeds the electron rest mass, requiring the consideration of relativistic effects. The relativistically correct ponderomotive potential is given by Up = ([1 + I[lambda]2/1.3 x 1018]1/2 - 1) moc2, where I[lambda]2 is the irradiance in W[mu]m2/cm2 and moc2 is the electron rest mass. At laser irradiance of I[lambda]2 ~ 1018 W[mu]m2/cm2, the ponderomotive potential can be of order several MeV. A few recent experiments--discussed in Chapter 3 of this thesis--consider this ponderomotive potential sufficiently strong to accelerate protons from the front surface of the target to energies up to tens of MeV. Another model, known as Target Normal Sheath Acceleration (TNSA), describes the mechanism as an electrostatic sheath on the back surface of the laser target. According to the TNSA model, relativistic hot electrons created at the laser-solid interaction penetrate the foil where a few escape to infinity. The remaining hot electrons are retained by the target potential and establish an electrostatic sheath on the back surface of the target.
Download or read book Intra pulse Dynamics of Laser driven Ion Acceleration in Ultra thin Foils written by Hersimerjit Padda and published by . This book was released on 2017 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: Through variation of the target foil thickness, the opening angle of the ring is shown to be correlated to the point in time during the laser pulse interaction at which the target becomes transparent to the laser (in a process termed relativistic induced transparency). The ring is largest when transparency occurs close to the peak of the laser intensity.
Download or read book Characterization and Optimization of Laser driven Ion Acceleration written by Kealan Naughton and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Relativistically Intense Laser Microplasma Interactions written by Tobias Ostermayr and published by Springer. This book was released on 2019-07-16 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation covers several important aspects of relativistically intense laser–microplasma interactions and some potential applications. A Paul-trap based target system was developed to provide fully isolated, well defined and well positioned micro-sphere-targets for experiments with focused peta-watt laser pulses. The laser interaction turned such targets into microplasmas, emitting proton beams with kinetic energies exceeding 10 MeV. The proton beam kinetic energy spectrum and spatial distribution were tuned by variation of the acceleration mechanism, reaching from broadly distributed spectra in relatively cold plasma expansions to spectra with relative energy spread as small as 20% in spherical multi-species Coulomb explosions and in directed acceleration processes. Numerical simulations and analytical calculations support these experimental findings and show how microplasmas may be used to engineer laser-driven proton sources. In a second effort, tungsten micro-needle-targets were used at a peta-watt laser to produce few-keV x-rays and 10-MeV-level proton beams simultaneously, both measured to have only few-μm effective source-size. This source was used to demonstrate single-shot simultaneous radiographic imaging with x-rays and protons of biological and technological samples. Finally, the dissertation discusses future perspectives and directions for laser–microplasma interactions including non-spherical target shapes, as well as thoughts on experimental techniques and advanced quantitative image evaluation for the laser driven radiography.
Download or read book Introduction to Evolutionary Computing written by Agoston E. Eiben and published by Springer Science & Business Media. This book was released on 2013-03-14 with total page 307 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first complete overview of evolutionary computing, the collective name for a range of problem-solving techniques based on principles of biological evolution, such as natural selection and genetic inheritance. The text is aimed directly at lecturers and graduate and undergraduate students. It is also meant for those who wish to apply evolutionary computing to a particular problem or within a given application area. The book contains quick-reference information on the current state-of-the-art in a wide range of related topics, so it is of interest not just to evolutionary computing specialists but to researchers working in other fields.
Download or read book Laser Driven Sources of High Energy Particles and Radiation written by Leonida Antonio Gizzi and published by Springer Nature. This book was released on 2019-09-05 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents a selection of articles based on inspiring lectures held at the “Capri” Advanced Summer School, an original event conceived and promoted by Leonida Antonio Gizzi and Ralph Assmann that focuses on novel schemes for plasma-based particle acceleration and radiation sources, and which brings together researchers from the conventional accelerator community and from the high-intensity laser-matter interaction research fields. Training in these fields is highly relevant for ultra-intense lasers and applications, which have enjoyed dramatic growth following the development of major European infrastructures like the Extreme Light Infrastructure (ELI) and the EuPRAXIA project. The articles preserve the tutorial character of the lectures and reflect the latest advances in their respective fields. The volume is mainly intended for PhD students and young researchers getting started in this area, but also for scientists from other fields who are interested in the latest developments. The content will also appeal to radiobiologists and medical physicists, as it includes contributions on potential applications of laser-based particle accelerators.
Download or read book Differential Evolution written by Kenneth Price and published by Springer Science & Business Media. This book was released on 2006-03-04 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: Problems demanding globally optimal solutions are ubiquitous, yet many are intractable when they involve constrained functions having many local optima and interacting, mixed-type variables. The differential evolution (DE) algorithm is a practical approach to global numerical optimization which is easy to understand, simple to implement, reliable, and fast. Packed with illustrations, computer code, new insights, and practical advice, this volume explores DE in both principle and practice. It is a valuable resource for professionals needing a proven optimizer and for students wanting an evolutionary perspective on global numerical optimization.
