Pub Date : 2018-08-01DOI: 10.1109/AAC.2018.8659400
Ethan M. Walker, R. Gilbertson, E. Simakov, G. Pilania, R. Muenchausen
“Logpile” photonic band gap structures are an attractive option for the construction of laser dielectric accelerators. In principle, these structures can be fabricated using a commercial Nanoscribe 3-D printer, although currently available resins do not meet the materials requirements necessary for a functional dielectric waveguide for laser accelerators. In particular, the requisite optical-frequency dielectric constant is well outside the range of conventional organic materials. This work examines material options for overcoming this barrier, while simultaneously meeting requirements for loss tangent, laser-induced breakdown, and compatibility with two-photon polymerization. We present computational screening of more exotic organics resins, and synthetic options for promising candidates. In addition, we discuss materials approaches involving metal-polymer complexes, as well as germanium and metal-chalcogenide polymer nanocomposites. Prospects, inherent limitations, and initial characterization of these various materials will be discussed in the context of 3D-printed dielectric accelerators.
{"title":"High-Dielectric 3-D Printable Materials for Laser Accelerators","authors":"Ethan M. Walker, R. Gilbertson, E. Simakov, G. Pilania, R. Muenchausen","doi":"10.1109/AAC.2018.8659400","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659400","url":null,"abstract":"“Logpile” photonic band gap structures are an attractive option for the construction of laser dielectric accelerators. In principle, these structures can be fabricated using a commercial Nanoscribe 3-D printer, although currently available resins do not meet the materials requirements necessary for a functional dielectric waveguide for laser accelerators. In particular, the requisite optical-frequency dielectric constant is well outside the range of conventional organic materials. This work examines material options for overcoming this barrier, while simultaneously meeting requirements for loss tangent, laser-induced breakdown, and compatibility with two-photon polymerization. We present computational screening of more exotic organics resins, and synthetic options for promising candidates. In addition, we discuss materials approaches involving metal-polymer complexes, as well as germanium and metal-chalcogenide polymer nanocomposites. Prospects, inherent limitations, and initial characterization of these various materials will be discussed in the context of 3D-printed dielectric accelerators.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114874058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.1109/AAC.2018.8659377
V. Teryaev, Yong Jiang, S. Shchelkunov, J. Hirshfield
Initial results are presented for the development of a continuous-wave highly-efficient radio-frequency (RF) source for applications at Thomas Jefferson National Accelerator Facility (TJNAF). The project goal is to design and demonstrate a compact CW multi-beam klystron amplifier (MBK) with a high efficiency (> 80%) capable of supplying 50 kW of RF power at 952.6 MHz. RF sources with these specifications are sought for the high-level RF system for ion acceleration in the Medium Energy Electron Ion Collider that is being developed at TJNAF.
{"title":"50kW CW Highly-Efficient Multi-Beam Klystron at 952 MHz for a Future Electron-Ion Collider","authors":"V. Teryaev, Yong Jiang, S. Shchelkunov, J. Hirshfield","doi":"10.1109/AAC.2018.8659377","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659377","url":null,"abstract":"Initial results are presented for the development of a continuous-wave highly-efficient radio-frequency (RF) source for applications at Thomas Jefferson National Accelerator Facility (TJNAF). The project goal is to design and demonstrate a compact CW multi-beam klystron amplifier (MBK) with a high efficiency (> 80%) capable of supplying 50 kW of RF power at 952.6 MHz. RF sources with these specifications are sought for the high-level RF system for ion acceleration in the Medium Energy Electron Ion Collider that is being developed at TJNAF.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128118149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.1109/AAC.2018.8659398
L. Lisi, J. Shaw, G. Tiwari, A. Hannasch, A. Bernstein, L. Labun, B. Hegelich, M. Downer
We present experimental results of a method that measures high flux, MeV scale x-rays produced via Thomson backscatter (TBS) of an intense laser pulse (ao ≈ 1) interacting with a counter-propagating Laser wakefield acceleration (LWFA) electron bunch. We predict the spectra of broadband 50–100 MeV TBS gamma-ray pulses in a single shot by combining two diagnostics - a pair-producing magnetic spectrometer and a cerium doped lutetium-yttrium oxyorthosilicate (LYSO(Ce)) scintillator - to capture two independent, cross-confirming signals. By combining these two diagnostics in a single shot, we are able to compare signal originating from pair production in the gamma-conversion spectrometer with the transverse electromagnetic shower profile in the LYSO scintillator, to deconvolve a photon spectrum. We make use of Geant4 [1] simulations and Thomson scattering theory [2] to theoretically reconstruct potential candidate spectra based on the LWFA electron energies and laser parameters, and, using a chi-squared fitting method, fit the signal simulated in Geant4 to signal measured on both detectors obtaining the most probable spectra. Below, we report a preliminary most probable spectrum with a mean energy of 60 MeV.
{"title":"Spectral Analysis of 50–100 MeV Thomson Backscatter Gamma-rays from GeV Laser-Plasma Accelerator","authors":"L. Lisi, J. Shaw, G. Tiwari, A. Hannasch, A. Bernstein, L. Labun, B. Hegelich, M. Downer","doi":"10.1109/AAC.2018.8659398","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659398","url":null,"abstract":"We present experimental results of a method that measures high flux, MeV scale x-rays produced via Thomson backscatter (TBS) of an intense laser pulse (ao ≈ 1) interacting with a counter-propagating Laser wakefield acceleration (LWFA) electron bunch. We predict the spectra of broadband 50–100 MeV TBS gamma-ray pulses in a single shot by combining two diagnostics - a pair-producing magnetic spectrometer and a cerium doped lutetium-yttrium oxyorthosilicate (LYSO(Ce)) scintillator - to capture two independent, cross-confirming signals. By combining these two diagnostics in a single shot, we are able to compare signal originating from pair production in the gamma-conversion spectrometer with the transverse electromagnetic shower profile in the LYSO scintillator, to deconvolve a photon spectrum. We make use of Geant4 [1] simulations and Thomson scattering theory [2] to theoretically reconstruct potential candidate spectra based on the LWFA electron energies and laser parameters, and, using a chi-squared fitting method, fit the signal simulated in Geant4 to signal measured on both detectors obtaining the most probable spectra. Below, we report a preliminary most probable spectrum with a mean energy of 60 MeV.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"624 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126355537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.1109/AAC.2018.8659437
S. Kuzikov, S. Antipov, A. Vikharev, Y. Danilov, E. Gomez
We consider three types of THz accelerating structures. The structures of the first type operate with relatively long THz pulses having narrow bandwidth. These structures are assumed to be fed by THz radiation produced by high-power rf sources like gyrotrons or by the drive electron beam. The mentioned structures exploit Bragg principles, in order to provide high shunt impedance as well as necessary mode selection. The dielectric structures of this type could be produced by a femtosecond laser ablation system developed at Euclid Techlabs. This technology had already been tested for production of a 270 GHz Photonic Band Gap (PBG) structure made out of high resistivity silicon. Recently, gradients on the order of ~1 GV/m were be obtained in a form of single cycle (~1 ps) THz pulses produced by conversion of a high peak power laser radiation in nonlinear crystals (~ mJ, 1 ps, up to 3 % conversion efficiency). These pulses however are broadband (0.1-5 THz) and therefore a new accelerating structure type is required. For electron beam acceleration with such pulses we consider conventional dielectric capillaries as well as arrays of parabolic micro-mirrors with common central.
{"title":"Quasi-Optical THz Accelerating Structures","authors":"S. Kuzikov, S. Antipov, A. Vikharev, Y. Danilov, E. Gomez","doi":"10.1109/AAC.2018.8659437","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659437","url":null,"abstract":"We consider three types of THz accelerating structures. The structures of the first type operate with relatively long THz pulses having narrow bandwidth. These structures are assumed to be fed by THz radiation produced by high-power rf sources like gyrotrons or by the drive electron beam. The mentioned structures exploit Bragg principles, in order to provide high shunt impedance as well as necessary mode selection. The dielectric structures of this type could be produced by a femtosecond laser ablation system developed at Euclid Techlabs. This technology had already been tested for production of a 270 GHz Photonic Band Gap (PBG) structure made out of high resistivity silicon. Recently, gradients on the order of ~1 GV/m were be obtained in a form of single cycle (~1 ps) THz pulses produced by conversion of a high peak power laser radiation in nonlinear crystals (~ mJ, 1 ps, up to 3 % conversion efficiency). These pulses however are broadband (0.1-5 THz) and therefore a new accelerating structure type is required. For electron beam acceleration with such pulses we consider conventional dielectric capillaries as well as arrays of parabolic micro-mirrors with common central.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125177234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.1109/AAC.2018.8659382
L. Amorim, N. Vafaei-Najafabadi
Although Plasma Wakefield Accelerators (PWFAs) can sustain accelerating gradients 100 times higher than conventional devices, the quality of the produced beams has been insufficient for future Free-Electron-Laser or Collider applications. To improve beam quality, through reducing energy spread, PWFAs typically operate in the beam-loaded nonlinear blowout regime. Here we show that in such regime, the accelerated beam can induce secondary ionization of plasma ions or neutral particles, and inject the released electrons into an additional low quality, high energy spread, beam called the “inception” beam. This work describes how the “inception” beam is formed in the PWFA that employs the Beam Induced Ionization Injection (BIII) technique. The supporting numerical study modeled the interaction of an electron beam with a hydrogen and helium gas, with the OSIRIS code, using the FACET beam parameters.
{"title":"Narrow “Inception” Beams Generated in FACET Beam-Driven Wakefield Accelerator Setups","authors":"L. Amorim, N. Vafaei-Najafabadi","doi":"10.1109/AAC.2018.8659382","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659382","url":null,"abstract":"Although Plasma Wakefield Accelerators (PWFAs) can sustain accelerating gradients 100 times higher than conventional devices, the quality of the produced beams has been insufficient for future Free-Electron-Laser or Collider applications. To improve beam quality, through reducing energy spread, PWFAs typically operate in the beam-loaded nonlinear blowout regime. Here we show that in such regime, the accelerated beam can induce secondary ionization of plasma ions or neutral particles, and inject the released electrons into an additional low quality, high energy spread, beam called the “inception” beam. This work describes how the “inception” beam is formed in the PWFA that employs the Beam Induced Ionization Injection (BIII) technique. The supporting numerical study modeled the interaction of an electron beam with a hydrogen and helium gas, with the OSIRIS code, using the FACET beam parameters.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131513520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.1109/AAC.2018.8659430
G. Sotnikov, T. Marshall, S. Shchelkunov, J. Hirshfield
The Dielectric Resonator Wakefield Accelerating (DWR) structure concept is presented. The DWR is a symmetric, rectangular dielectric loaded unit consisting of a central channel bordered by two narrow side channels; four slabs of dielectric are used to form the channels. The device is configured as a resonator, having reflectors at each end, which may be tuned to reflect only the desired wakefield modes. One or more drive bunches can traverse the central channel and set up intense wakefields that will accelerate a pair of witness bunches located in the narrow side channels and achieve an elevated transformer ratio. Accordingly, there is no need for a separate “transformer” structure. The proposed device is to operate at 285 GHz, providing a gradient of 500 MV/m after injection of 40, 2.5nC high energy drive electron bunches. This resonator can accommodate elongated bunches and operates in a nearly-single wakefield mode in which the transverse force on electrons accelerated at the center of the witness channel is small in comparison with the longitudinal force.
{"title":"The Dielectric Resonator Wakefield Accelerator","authors":"G. Sotnikov, T. Marshall, S. Shchelkunov, J. Hirshfield","doi":"10.1109/AAC.2018.8659430","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659430","url":null,"abstract":"The Dielectric Resonator Wakefield Accelerating (DWR) structure concept is presented. The DWR is a symmetric, rectangular dielectric loaded unit consisting of a central channel bordered by two narrow side channels; four slabs of dielectric are used to form the channels. The device is configured as a resonator, having reflectors at each end, which may be tuned to reflect only the desired wakefield modes. One or more drive bunches can traverse the central channel and set up intense wakefields that will accelerate a pair of witness bunches located in the narrow side channels and achieve an elevated transformer ratio. Accordingly, there is no need for a separate “transformer” structure. The proposed device is to operate at 285 GHz, providing a gradient of 500 MV/m after injection of 40, 2.5nC high energy drive electron bunches. This resonator can accommodate elongated bunches and operates in a nearly-single wakefield mode in which the transverse force on electrons accelerated at the center of the witness channel is small in comparison with the longitudinal force.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120953234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.1109/AAC.2018.8659387
Tianhong Wang, V. Khudik, G. Shvets
We report the focusing of a shaped thin target by a circular-polarized laser pulse at 1022 W/cm2 intensity, to a low-emittance, quasi-monoenergetic proton beam. The target shape is designed to be simultaneously deformed and focused into a cubic micron spot by the radiation pressure during its acceleration. A simple model reminiscent of geometric optics of the ions is developed. The model predicts the self-consistent dynamics of the nanostructured thin target, as well as the targets shape that is necessary for focusing without aberrations. Three-dimensional particle-in-cell simulations show that the focal length and the final energy are in good agreement with the scaling laws obtained from the geometric optics model. Extensive scans of the laser and target parameters identify the stable propagation regime where the Rayleigh-Taylor (RT)-like instability is suppressed. Stable focusing is found at different laser powers (from petawatt to multi-petawatt). Focused proton beam with number density of order 1023 cm−3 and energy density up to 2×1013 J/cm3 at the focal point is observed in simulation with laser power 35 PW.
{"title":"High Energy Density Ion Beam from a Focusing Shaped Target in the Radiation Pressure Regime","authors":"Tianhong Wang, V. Khudik, G. Shvets","doi":"10.1109/AAC.2018.8659387","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659387","url":null,"abstract":"We report the focusing of a shaped thin target by a circular-polarized laser pulse at 1022 W/cm2 intensity, to a low-emittance, quasi-monoenergetic proton beam. The target shape is designed to be simultaneously deformed and focused into a cubic micron spot by the radiation pressure during its acceleration. A simple model reminiscent of geometric optics of the ions is developed. The model predicts the self-consistent dynamics of the nanostructured thin target, as well as the targets shape that is necessary for focusing without aberrations. Three-dimensional particle-in-cell simulations show that the focal length and the final energy are in good agreement with the scaling laws obtained from the geometric optics model. Extensive scans of the laser and target parameters identify the stable propagation regime where the Rayleigh-Taylor (RT)-like instability is suppressed. Stable focusing is found at different laser powers (from petawatt to multi-petawatt). Focused proton beam with number density of order 1023 cm−3 and energy density up to 2×1013 J/cm3 at the focal point is observed in simulation with laser power 35 PW.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128896442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.1109/AAC.2018.8659414
B. Beaudoin, I. Haber, R. Kishek, T. Antonsen
We present results of longitudinally compressing a beam bunch by inwardly displacing both the head and tail end focusing fields used to contain the beam. This method of compression is different from the conventional velocity tilt method that rotates the beam in phase space. Simulation and experimental results are presented at numerous compression rates. The results described below assume an injected longitudinal current profile into the University of Maryland Electron Ring (UMER) that is uniform both in current and velocity.
{"title":"Head and Tail Compression of an Electron Beam","authors":"B. Beaudoin, I. Haber, R. Kishek, T. Antonsen","doi":"10.1109/AAC.2018.8659414","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659414","url":null,"abstract":"We present results of longitudinally compressing a beam bunch by inwardly displacing both the head and tail end focusing fields used to contain the beam. This method of compression is different from the conventional velocity tilt method that rotates the beam in phase space. Simulation and experimental results are presented at numerous compression rates. The results described below assume an injected longitudinal current profile into the University of Maryland Electron Ring (UMER) that is uniform both in current and velocity.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114791706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.1109/AAC.2018.8659436
Kathleen E. Hamilton, Levon Dovlatvan, D. Matthew, D. Sutter, S. Bernal, T. Antonsen, B. Beaudoin
The University of Maryland Electron Ring (UMER) is a dedicated research accelerator facility for studying the physics of high-intensity charged particle beams. Advancing the capabilities of the longitudinal confinement system paves the way for multi-bunch electron confinement, allowing UMER to extend its performance and modes of operation for various experiments on longitudinal dynamics. The research reported here employs an existing induction cell [1], and a radiofrequency (RF) amplifier to mimic traditional RF cavity confinement. By applying sinusoidal RF waves at the revolution frequency with synchronous phase angle equal to zero, we can confine an electron beam in the wave's linear regions. To additionally combat particle loss, we calculated the separatrices-the areas of phase space within which the beam is longitudinally confined-with a central synchronous particle.
{"title":"Implementing Traditional Longitudinal Beam Focusing in UMER","authors":"Kathleen E. Hamilton, Levon Dovlatvan, D. Matthew, D. Sutter, S. Bernal, T. Antonsen, B. Beaudoin","doi":"10.1109/AAC.2018.8659436","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659436","url":null,"abstract":"The University of Maryland Electron Ring (UMER) is a dedicated research accelerator facility for studying the physics of high-intensity charged particle beams. Advancing the capabilities of the longitudinal confinement system paves the way for multi-bunch electron confinement, allowing UMER to extend its performance and modes of operation for various experiments on longitudinal dynamics. The research reported here employs an existing induction cell [1], and a radiofrequency (RF) amplifier to mimic traditional RF cavity confinement. By applying sinusoidal RF waves at the revolution frequency with synchronous phase angle equal to zero, we can confine an electron beam in the wave's linear regions. To additionally combat particle loss, we calculated the separatrices-the areas of phase space within which the beam is longitudinally confined-with a central synchronous particle.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117139882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.1109/AAC.2018.8659384
B. Beaudoin, I. Haber, R. Kishek, T. Antonsen
Instability develops in a long space-charge dominated beam when it is allowed to coast in a storage ring without RF containment. The longitudinal space-charge forces in these intense beams cause it to expand axially, closing on itself and as a result wrapping the accelerator. Simulations and experimental measurements indicate that instability occurs when the leading and trailing ends of the beam spatially overlap the body of the beam. The overlapping beam segments have different velocities, which is the energy source for the instability. Two instabilities have been identified in simulations: a traditional longitudinal two-stream, and a coupled betatron, two stream instability.
{"title":"Multi-Stream Instability in UMER","authors":"B. Beaudoin, I. Haber, R. Kishek, T. Antonsen","doi":"10.1109/AAC.2018.8659384","DOIUrl":"https://doi.org/10.1109/AAC.2018.8659384","url":null,"abstract":"Instability develops in a long space-charge dominated beam when it is allowed to coast in a storage ring without RF containment. The longitudinal space-charge forces in these intense beams cause it to expand axially, closing on itself and as a result wrapping the accelerator. Simulations and experimental measurements indicate that instability occurs when the leading and trailing ends of the beam spatially overlap the body of the beam. The overlapping beam segments have different velocities, which is the energy source for the instability. Two instabilities have been identified in simulations: a traditional longitudinal two-stream, and a coupled betatron, two stream instability.","PeriodicalId":339772,"journal":{"name":"2018 IEEE Advanced Accelerator Concepts Workshop (AAC)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114185824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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