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Beam Instability And Microbunching Due To Coherent Synchrotron Radiation
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Book Synopsis Beam Instability and Microbunching Due to Coherent Synchrotron Radiation by :
Download or read book Beam Instability and Microbunching Due to Coherent Synchrotron Radiation written by and published by . This book was released on 2001 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: A relativistic electron beam moving on a circular orbit in free space can radiate coherently if the wavelength of the synchrotron radiation exceeds the length of the bunch. In accelerators coherent synchrotron radiation (CSR) of the bunch is usually suppressed by the shielding effect of the conducting walls of the vacuum chamber. However an initial density fluctuations with a characteristic length much shorter than the bunch length can radiate coherently. If the radiation results in the growth of the initial fluctuation, one can expect an instability which leads to micro-bunching of the beam and increased coherent radiation at short wavelengths. Such an instability is studied theoretically in this paper. The effect of the beam energy spread and the shielding due to the conducting walls is included into consideration. The condition for the instability is evaluated for several existing accelerators.
Book Synopsis Theory and Observations of Microbunching Instability in Electron Machines by :
Download or read book Theory and Observations of Microbunching Instability in Electron Machines written by and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: For not very short bunches, the coherent synchrotron radiation (CSR) is usually suppressed by the shielding effect of the conducting walls of the vacuum chamber. However an initial density fluctuation in the beam with a characteristic length much shorter than the bunch length can radiate coherently. If the radiation-reaction force drives growth of the initial fluctuation, one can expect an instability which leads to micro-bunching of the beam and increased coherent radiation at short wavelengths. It has recently been realized that such an instability can play an important role in electron/positron rings where it often manifests itself as a bursting of radiation in the range of hundreds of gigahertz or terahertz. This instability can also be a source of an undesirable emittance growth in bunch compressors used in the next generation short-wavelength FELs. In this paper, we review progress in theoretical studies and numerical simulations of the microbunching instability and show connection of the theory to recent observations in electron machines.
Book Synopsis Suppression of Microbunching Instability in the Linac Coherent Light Source by :
Download or read book Suppression of Microbunching Instability in the Linac Coherent Light Source written by and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: A microbunching instability driven by longitudinal space charge, coherent synchrotron radiation, and linac wakefields is studied for the linac coherent light source (LCLS) accelerator system. Since the uncorrelated (local) energy spread of electron beams generated from a photocathode rf gun is very small, the microbunching gain may be large enough to significantly amplify rf-gun generated modulations or even shot-noise fluctuations of the electron beam. The uncorrelated energy spread can be increased by an order of magnitude to provide strong Landau damping against the instability without degrading the free-electron laser performance. We study different damping options in the LCLS and discuss an effective laser heater to minimize the impact of the instability on the quality of the electron beam.
Book Synopsis Nonlinear Stage of the Microbunching by Coherent Synchrotron Radiation by :
Download or read book Nonlinear Stage of the Microbunching by Coherent Synchrotron Radiation written by and published by . This book was released on 2001 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coherent synchrotron radiation can lead to the microwave instability. In this note, we consider saturation of the most unstable mode close to the threshold of instability.
Download or read book Produktion Paris 1930 written by and published by . This book was released on 1930 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Coherent Synchrotron Radiation Diagnostics for Investigating the Longitudinal Microbunching Instability at Diamond Light Source by : William Shields
Download or read book Coherent Synchrotron Radiation Diagnostics for Investigating the Longitudinal Microbunching Instability at Diamond Light Source written by William Shields and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Much Ado about Microbunching by : Daniel F. Ratner
Download or read book Much Ado about Microbunching written by Daniel F. Ratner and published by Stanford University. This book was released on 2011 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: The push to provide ever brighter coherent radiation sources has led to the creation of correspondingly bright electron beams. With billions of electrons packed into normalized emittances (phase space) below one micron, collective effects may dominate both the preservation and use of such ultra-bright beams. An important class of collective effects is due to density modulations within the bunch, or microbunching. Microbunching may be deleterious, as in the case of the Mi- crobunching Instability (MBI), or it may drive radiation sources of unprecedented intensity, as in the case of Free Electron Lasers (FELs). In this work we begin by describing models of microbunching due to inherent beam shot noise, which sparks both the MBI as well as SLAC's Linac Coherent Light Source, the world's first hard X-ray laser. We first use this model to propose a mechanism for reducing the inherent beam shot noise as well as for predicting MBI effects. We then describe experimental measurements of the resulting microbunching at LCLS, including optical radiation from the MBI, as well as the first gain length and harmonic measurements from a hard X-ray FEL. In the final chapters, we describe schemes that use external laser modulations to microbunch light sources of the future. In these sections we describe coherent light source schemes for both both linacs and storage rings.
Book Synopsis Petri Danielis Huetii, Episcopi Abringensis, Commentarius de rebus ad eum pertinentibus by :
Download or read book Petri Danielis Huetii, Episcopi Abringensis, Commentarius de rebus ad eum pertinentibus written by and published by . This book was released on 1719 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Beam Breakup Instability and Coherent Synchrotron Radiation Limits of the Particle Accelerator CBETA by : William Lou
Download or read book Beam Breakup Instability and Coherent Synchrotron Radiation Limits of the Particle Accelerator CBETA written by William Lou and published by . This book was released on 2020 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: The construction of Cornell BNL Energy-Recovery-Linac Test Accelerator (CBETA) was completed at Cornell University's Wilson Laboratory in 2019. CBETA is designed to accelerate electrons from 6 MeV to 150 MeV in four linac passes using a single Fixed Field Alternating gradient (FFA) return beamline accepting all energies from 42 to 150 MeV. Energy recovery is achieved by decelerating the beam within the Superconducting Radio Frequency (SRF) cavities, in which the beam returns energy to the electromagnetic field. Energy recovery allows CBETA to produce a beam current much higher than with conventional storage rings. This thesis focuses on two important limits of CBETA: the beam current limit due to Beam Breakup (BBU) instability and the bunch charge limit due to Coherent Synchrotron Radiation (CSR) effects. For BBU, elementary theories are revisited to benchmark the simulation codes. Additional theory regarding the scaling law of the threshold current and the effect of chromaticity are also investigated. For CSR, a new "2-bend" theory has been developed by extending the conventional 1-bend theory using the Lienard-Wiechert formula. The new theory is essential to describe CSR wake propagation when magnets are located close to each other, as in CBETA. These new theories could benefit designs and researches of future ERLs. For both topics, extensive simulations have been performed using the software developed by Cornell University, Bmad.
Book Synopsis Diagnostics of Short Electron Bunches with THz Detectors in Particle Accelerators by : Steinmann, Johannes Leonhard
Download or read book Diagnostics of Short Electron Bunches with THz Detectors in Particle Accelerators written by Steinmann, Johannes Leonhard and published by KIT Scientific Publishing. This book was released on 2019-04-23 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Microbunching Instability Due to Bunch Compression by :
Download or read book Microbunching Instability Due to Bunch Compression written by and published by . This book was released on 2005 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic bunch compressors are designed to increase the peak current while maintaining the transverse and longitudinal emittances in order to drive a short-wavelength free electron laser (FEL). Recently, several linac-based FEL experiments observe self-developing micro-structures in the longitudinal phase space of electron bunches undergoing strong compression [1-3]. In the mean time, computer simulations of coherent synchrotron radiation (CSR) effects in bunch compressors illustrate that a CSR-driven microbunching instability may significantly amplify small longitudinal density and energy modulations and hence degrade the beam quality [4]. Various theoretical models have since been developed to describe this instability [5-8]. It is also pointed out that the microbunching instability may be driven strongly by the longitudinal space charge (LSC) field [9,10] and by the linac wakefield [11] in the accelerator, leading to a very large overall gain of a two-stage compression system such as found in the Linac Coherent Light Source (LCLS) [12]. This paper reviews theory and simulations of microbunching instability due to bunch compression, the proposed method to suppress its effects for short-wavelength FELs, and experimental characterizations of beam modulations in linear accelerators. A related topic of interests is microbunching instability in storage rings, which has been reported in the previous ICFA beam dynamics newsletter No. 35 (http://wwwbd. fnal.gov/icfabd/Newsletter35.pdf).
Book Synopsis Single-mode Coherent Synchrotron Radiation Instability by :
Download or read book Single-mode Coherent Synchrotron Radiation Instability written by and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The microwave instability driven by the coherent synchrotron radiation (CSR) has been previously studied neglecting effect of the shielding caused by the finite beam pipe aperture. In practice, the unstable mode can be close to the shielding threshold where the spectrum of the radiation in a toroidal beam pipe is discrete. In this paper, the CSR instability is studied in the case when it is driven by a single synchronous mode. A system of equations for the beam-wave interaction is derived and its similarity to the 1D FEL theory is demonstrated. In the linear regime, the growth rate of the instability is obtained and a transition to the case of continuous spectrum is discussed. The nonlinear evolution of the single-mode instability, both with and without synchrotron damping and quantum diffusion, is also studied.
Book Synopsis Vlasov Analysis of Microbunching Gain for Magnetized Beams by :
Download or read book Vlasov Analysis of Microbunching Gain for Magnetized Beams written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: For a high-brightness electron beam with low energy and high bunch charge traversing a recirculation beamline, coherent synchrotron radiation and space charge effect may result in the microbunching instability (MBI). Both tracking simulation and Vlasov analysis for an early design of Circulator Cooler Ring for the Jefferson Lab Electron Ion Collider reveal significant MBI. It is envisioned these could be substantially suppressed by using a magnetized beam. In this work, we extend the existing Vlasov analysis, originally developed for a non-magnetized beam, to the description of transport of a magnetized beam including relevant collective effects. The new formulation will be further employed to confirm prediction of microbunching suppression for a magnetized beam transport in a recirculating machine design.
Book Synopsis Effects of Linac Wakefield on CSR Microbunching in the Linac Coherent Light Source by :
Download or read book Effects of Linac Wakefield on CSR Microbunching in the Linac Coherent Light Source written by and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The design of the Linac Coherent Light Source (LCLS) requires two-stage bunch compression for stability against timing and charge jitters. Coherent synchrotron radiation (CSR) induced in these bunch compressors can drive a microbunching instability that may degrade the beam brightness. In this paper, we study effects of the longitudinal wakefield in the accelerator on this instability. We show that significant energy modulation can be accumulated in the linac through the geometrical wakefield and can enhance the CSR microbunching in these compressors. Analytical calculations are compared with numerical simulations to evaluate the gain of microbunching for the entire LCLS accelerator system.
Book Synopsis Reversible Electron Beam Heating for Suppression of Microbunching Instabilities at Free-Electron Lasers by :
Download or read book Reversible Electron Beam Heating for Suppression of Microbunching Instabilities at Free-Electron Lasers written by and published by . This book was released on 2012 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: The presence of microbunching instabilities due to the compression of high-brightness electron beams at existing and future x-ray free-electron lasers (FELs) results in restrictions on the attainable lasing performance and renders beam imaging with optical transition radiation impossible. The instability can be suppressed by introducing additional energy spread, i.e., heating the electron beam, as demonstrated by the successful operation of the laser heater system at the Linac Coherent Light Source. The increased energy spread is typically tolerable for self-amplified spontaneous emission FELs but limits the effectiveness of advanced FEL schemes such as seeding. In this paper, we present a reversible electron beam heating system based on two transverse deflecting radio-frequency structures (TDSs) upstream and downstream of a magnetic bunch compressor chicane. The additional energy spread is introduced in the first TDS, which suppresses the microbunching instability, and then is eliminated in the second TDS. We show the feasibility of the microbunching gain suppression based on calculations and simulations including the effects of coherent synchrotron radiation. Acceptable electron beam and radio-frequency jitter are identified, and inherent options for diagnostics and on-line monitoring of the electron beam's longitudinal phase space are discussed.
Book Synopsis Microbunching and Coherent Synchrotron Radiation in Linear Free Electron Lasers by : Alexander Brynes
Download or read book Microbunching and Coherent Synchrotron Radiation in Linear Free Electron Lasers written by Alexander Brynes and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Investigation of Microbunching Instabilities in Modern Recirculating Accelerators by :
Download or read book Investigation of Microbunching Instabilities in Modern Recirculating Accelerators written by and published by . This book was released on 2017 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: Particle accelerators are machines to accelerate and store charged particles, such as electrons or protons, to the energy levels for various scientific applications. A collection of charged particles usually forms a particle beam. There are three basic types of particle accelerators: linear accelerators (linac), storage-ring (or circular) accelerators, and recirculating accelerators. In a linac, particles are accelerated and pass through once along a linear or straight beamline. Storage-ring accelerators propel particles around a circular track and repetitively append the energy to the stored beam. The third type, also the most recent one in chronology, the recirculating accelerator, is designed to accelerate the particle beam in a short section of linac, circulate the beam, and then either continue to accelerate for energy boost or decelerate it for energy recovery. The beam properties of a linac machine are set at best by the initial particle sources. For storage rings, the beam equilibria are instead determined by the overall machine design. The modern recirculating machines share with linacs the advantages to both accelerate and preserve the beam with high beam quality, as well as efficiently reuse the accelerating components. The beamline design in such a machine configuration can however be much more complicated than that of linacs. As modern accelerators push toward the high-brightness or high-intensity frontier by demanding particles in a highly charged bunch (about nano-Coulomb per bunch) to concentrate in an ever-decreasing beam phase space (transverse normalized emittance about 1 [mu]m and relative energy spread of the order of 10^-5 in GeV beam energy), the interaction amongst particles via their self-generated electromagnetic fields can potentially lead to coherent instabilities of the beam and thus pose significant challenges to the machine design and operation. In the past decade and a half, microbunching instability (MBI) has been one of the most challenging issues for such high-brightness or high-intensity beam transport, as it would degrade lasing performance in the fourth-generation light sources, reduce cooling efficiency in electron cooling facilities, and compromise the luminosity of colliding beams in lepton or lepton-hadron colliders. The dissertation work will focus on the MBI in modern recirculating electron accelerators. It has been known that the collective interactions, the coherent synchrotron radiation (CSR) and the longitudinal space charge (LSC) forces, can drive MBI. The CSR effect is a collective phenomenon in which the electrons in a curved motion, e.g. a bending dipole, emit radiation at a scale comparable to the micro-bunched structure of the bunch distribution. The LSC effect stems from non-uniformity of the charge distribution, acts as plasma oscillation, and can eventually accumulate an amount of energy modulation when the beam traverses a long section of a beamline. MBI can be seeded by non-uniformity or shot noise of the beam, which originates from granularity of the elementary charge. Through the aforementioned collective effects, the modulation of the bunch sub-structure can be amplified and, once the beam-wave interaction formed a positive feedback, can result in MBI. The problem of MBI has been intensively studied for linac-based facilities and for storage-ring accelerators. However, systematic studies for recirculation machines are still very limited and form a knowledge gap. Because of the much more complicated machine configuration of the recirculating accelerators than that of linacs, the existing MBI analysis needs to be extended to accommodate the high-brightness particle beam transport in modern recirculating accelerators. This dissertation is focused on theoretical investigation of MBI in such machine configuration in the following seven themes: (1) Development and generalization of MBI theory The theoretical formulation has been extended so as to be applicable to a genera ...
