Simulating the dynamical friction force on ions due to a briefly co-propagating electron beam

Bell, George I.; Bruhwiler, David L.; Fedotov, A. V.; Sobol, A.; Busby, R.; Stoltz, Peter; Abell, Dan T.; Messmer, Peter; Ben‐Zvi, I.; Litvinenko, Vladimir

doi:10.1016/j.jcp.2008.06.019

Cited by 8 publications

(6 citation statements)

References 22 publications

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“…C. An ion which moves longitudinally at speed 2.93×10 5 m/s (the electron longitudinal thermal speed).…”

Section: Simulation Resultsmentioning

confidence: 99%

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Modulator simulations for coherent electron cooling using a variable density electron beam

Bell,

Pogorelov,

Schwartz

et al. 2014

Preprint

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Increasing the luminosity of relativistic hadron beams is critical for the advancement of nuclear physics. Coherent electron cooling (CEC) promises to cool such beams significantly faster than alternative methods. We present simulations of 40 GeV/nucleon Au+79 ions through the first (modulator) section of a coherent electron cooler. In the modulator, the electron beam copropagates with the ion beam, which perturbs the electron beam density and velocity via anisotropic Debye shielding. In contrast to previous simulations, where the electron density was constant in time and space, here the electron beam has a finite transverse extent, and undergoes focusing by quadrupoles as it passes through the modulator. The peak density in the modulator increases by a factor of 3, as specified by the beam Twiss parameters. The inherently 3D particle and field dynamics is modeled with the parallel VSim framework using a δf PIC algorithm. Physical parameters are taken from the CEC proof-of-principle experiment under development at Brookhaven National Lab.

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“…C. An ion which moves longitudinally at speed 2.93×10 5 m/s (the electron longitudinal thermal speed).…”

Section: Simulation Resultsmentioning

confidence: 99%

“…The electron density in the beam changes in space as well as in time. Simulation results are calculated using VSim (formerly Vorpal) [5] using δf PIC [3]. The δf particles do not represent deviations of the beam from a steady-state, but rather deviations of the beam away from the known solution described by Twiss parameters.…”

Section: Introductionmentioning

confidence: 99%

Modulator simulations for coherent electron cooling using a variable density electron beam

Bell,

Pogorelov,

Schwartz

et al. 2014

Preprint

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“…The initial effort established confidence in the new algorithms implemented within the parallel Versatile Object-oriented Relativistic Plasma Analysis with Lasers (VORPAL) framework, and contributed directly to the solenoid-based design. Subsequent algorithmic improvements and additional VORPAL simulations (Bell et al 2008) confirmed the conjecture that the magnetic fields of the undulator would only reduce the friction force logarithmically and, thus, be a much cheaper yet viable alternative. Although detailed cost estimates are not available, it is agreed that the modified design for the RHIC electron cooler would be tens of millions of dollars less expensive than the previous design, with much lower technical risk.…”

Section: Past Experiences and Current Capabilitiesmentioning

confidence: 87%

Scientific Challenges for Understanding the Quantum Universe

Khaleel¹

2009

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The scientific grand challenges for this field are described in several publications, including the High Energy Physics Advisory Panel's (HEPAP) Quantum Universe report and the P5 subcommittee's Long Range Plan for Particle Physics in the United States. From these, the following fundamental questions are posed: What are the main features of physics Beyond the Standard Model? These can be sought by exploring physics at high energy using the Large Hadron Collider (LHC), by seeking small departures from predictions made assuming Standard Model physics for interactions at lower energy, or by exploring physics with neutrinos. What is the identity of dark matter and how does large scale structure develop in the expanding universe? The prime dark matter candidate is a supersymmetric particle, but less massive particles called axions may also be involved. The primordial fluctuations out of which contemporary largescale structure grew may provide a window on fundamental processes occurring during the epoch of inflation. What are the empirical properties of dark energy and what do they imply about its nature? Present evidence involving observations of supernova explosions and the growth of perturbations in the expanding universe is consistent with it having the properties of Einstein's cosmological constant.Departures from this behavior may signify the presence of new physics operating over cosmological scales. What are the reasons for and implications of neutrino masses? The measured properties of neutrinos provide an existence proof for important physics Beyond the Standard Model (BSM) but may also lead to an explanation of why there is a net preponderance of matter over anti-matter. Astrophysical arguments also contribute to the answer. Are there extra dimensions beyond the three spatial and single temporal dimensions familiar from everyday experience? These may have tiny length scales as suggested by string theory or may have macroscopic scales that can lead to a weakening of the law of gravity. How do Nature's particle accelerators operate in extreme environments? Ultra high energy cosmic rays are accelerated by cosmic sources possibly associated with massive black holes to energies as high as 1 ZeV. When these cosmic rays hit the Earth's atmosphere, they do so with center of momentum energies in excess of 100 TeV. While we can observe cataclysmic events such as a supernova explosion or the collapse of a massive star into a black hole from a vast distance, these involve phenomena that can never be reproduced in a terrestrial laboratory. However, it becomes increasingly possible to recreate these conditions in a digital universe where important questions can be asked and alternatives explored.The planning and design of the International Linear Collider (ILC) is critical for the next step in high energy physics. How can we be certain that this expensive machine will work when it is turned on? Instead of building a series of increasingly costly prototypes, accelerator physicists turn with increasing sophistication...

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“…Cooling systems have not been built for EIC parameters, but simulations using high-performance computers with the VORPAL® 1 framework (Nieter and Cary 2004) have resolved differences in analytical models for the dynamical friction force in magnetized cooling systems (Fedotov et al 2006). These (parallel) simulations have also quantitatively shown how the friction would be reduced if the typical high-field solenoid magnet is replaced with a conventional (and much less expensive) undulator (Bell et al 2008). As shown in Figure 32, the friction force is reduced logarithmically with the undulator field strength.…”

Section: Design Of Electron Cooling Systems For Nuclear Physics Applimentioning

confidence: 99%

“…Image courtesy of Robert Ryne (Lawrence Berkeley National Laboratory). Parallel VORPAL simulations showing logarithmic reduction of the dynamic friction force in an undulator-based electron cooling system(Bell et al 2008).…”

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confidence: 99%

Scientific Grand Challenges: Forefront Questions in Nuclear Science and the Role of High Performance Computing

Khaleel¹

2009

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EXECUTIVE SUMMARY Nuclear physics is manifest in areas as seemingly disparate as the history of the early universe, the generation of energy in the sun, and the creation of nearly all the elements in stellar furnaces and explosions. A major focus of nuclear physics is the strong force and the atomic nuclei whose binding is a direct result of it, and whose stability underlies that of the atoms and thus molecules forming the familiar matter of all life forms and everyday objects. The strong nuclear force is a complex one, much more so than the gravitational and electromagnetic forces familiar from daily life. Understanding this nuclear force places particularly difficult demands not only on experiment but also on theory and calculation, particularly on computational power needed for these calculations. Nuclear physics pursues several major areas of research, including the following: 1. Structure of nuclei 2. Nuclear forces and quantum chromodynamics (QCD), the quantum field theory of the strong interaction 3. Fundamental interactions and symmetries that govern the interactions and the quantum states observed 4. Nuclear astrophysics and the synthesis of nuclei in stars and elsewhere in the cosmos 5. Hot QCD for the highest temperatures known and phases of strongly interacting matter 6. Science and design of the accelerators, detectors, and other tools essential for pursuing these scientific questions. The analysis and interpretation of results, and the development of an encompassing theoretical and intellectual framework depend on significant and focused investments, particularly in large-scale computing facilities and their ancillary capabilities for data visualization, storage, retrieval and transmittal. These are necessary in parallel to the perhaps more familiar investments in state-of-the-art accelerators and detectors to support experimental investigations. Most forefront problems now driving active research depend on access to large-scale computing facilities for tasks ranging from designing the facilities, making predictions based on current theories, and determining the implications for scientists' overall understanding of the experimental results, all with more demanding requirements for precision. The scale of computing facilities needed for state-of-the-art scientific exploration far outweighs what is possible with desktop-to departmental-scale (few to hundreds of computing cores) resources-instead, requiring access to the (few) large national centers where tens of thousands of computing cores, capable of delivering sustained performance of hundreds of teraflops, are available. Many problems, coming from all areas of nuclear physics, still require that significant approximations be made before such powerful centers can process the problem, or cannot even be attempted at present centers as they require computing timescales on the order of years. Extrapolating to the computing power needed to remove such approximations indicates a major shift in the ability to address such forefront questions that will oc...

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Simulating the dynamical friction force on ions due to a briefly co-propagating electron beam

Cited by 8 publications

References 22 publications

Modulator simulations for coherent electron cooling using a variable density electron beam

Modulator simulations for coherent electron cooling using a variable density electron beam

Scientific Challenges for Understanding the Quantum Universe

Scientific Grand Challenges: Forefront Questions in Nuclear Science and the Role of High Performance Computing

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