66 research outputs found
Recommended from our members
Wakefield Computations for the CLIC PETS using the Parallel Finite Element Time-Domain Code T3P
In recent years, SLAC's Advanced Computations Department (ACD) has developed the high-performance parallel 3D electromagnetic time-domain code, T3P, for simulations of wakefields and transients in complex accelerator structures. T3P is based on advanced higher-order Finite Element methods on unstructured grids with quadratic surface approximation. Optimized for large-scale parallel processing on leadership supercomputing facilities, T3P allows simulations of realistic 3D structures with unprecedented accuracy, aiding the design of the next generation of accelerator facilities. Applications to the Compact Linear Collider (CLIC) Power Extraction and Transfer Structure (PETS) are presented
Recommended from our members
Simulating Dark Current in NLC Structures
Dark current generation and capture are of great importance in high gradient accelerating structure R&D especially for the NLC which aims to operate at 65 MV/m with specific limits on dark current and RF breakdown rates. Although considerable effort has been devoted to building and testing various types of structures to meet these requirements, few theoretical studies have been done to understand these effects in actual structures. This paper focuses on the simulation of dark current in a NLC test structure for which experimental data are available. The parallel time-domain field solver Tau3P and the parallel particle tracking code Track3P are used together to simulate, for the first time, a dark current pulse to compare with the data measured downstream. Results from SLAC X-band 30-cell constant impedance structure for RF drive pulses with different rise times are presented and discussed
Recommended from our members
Computational Science Research in Support of Petascale Electromagnetic Modeling
Computational science research components were vital parts of the SciDAC-1 accelerator project and are continuing to play a critical role in newly-funded SciDAC-2 accelerator project, the Community Petascale Project for Accelerator Science and Simulation (ComPASS). Recent advances and achievements in the area of computational science research in support of petascale electromagnetic modeling for accelerator design analysis are presented, which include shape determination of superconducting RF cavities, mesh-based multilevel preconditioner in solving highly-indefinite linear systems, moving window using h- or p- refinement for time-domain short-range wakefield calculations, and improved scalable application I/O
Recommended from our members
Parallel Finite Element Particle-In-Cell Code for Simulations of Space-charge Dominated Beam-Cavity Interactions
Over the past years, SLAC's Advanced Computations Department (ACD) has developed the parallel finite element (FE) particle-in-cell code Pic3P (Pic2P) for simulations of beam-cavity interactions dominated by space-charge effects. As opposed to standard space-charge dominated beam transport codes, which are based on the electrostatic approximation, Pic3P (Pic2P) includes space-charge, retardation and boundary effects as it self-consistently solves the complete set of Maxwell-Lorentz equations using higher-order FE methods on conformal meshes. Use of efficient, large-scale parallel processing allows for the modeling of photoinjectors with unprecedented accuracy, aiding the design and operation of the next-generation of accelerator facilities. Applications to the Linac Coherent Light Source (LCLS) RF gun are presented
Relative deprivation and inequalities in social and political activism
In this paper we analyse whether relative deprivation has divergent effects on different types of social and political action. We expect that it will depress volunteering with parties as well as different types of conventional political participation more generally while stimulating volunteering with anti-cuts organisations and engagement in various kinds of protest activism. There is little research into how relative deprivation impacts on different types of social and political action from the wide range of activities available to citizens in contemporary democracies as well as into how this relationship might vary based on the wider economic context. While many studies construct scales, we examine participation in specific activities and associations, such as parties or anti-cuts organisations, voting, contacting, demonstrating and striking to show that deprivation has divergent effects that depart from what is traditionally argued. We apply random effects models with cross-level interactions utilizing an original cross-national European dataset collected in 2015 (N = 17,667) within a collaborative funded-project. We show that a negative economic context has a mobilizing effect by both increasing the stimulating effect of relative deprivation on protest activism as well as by closing or reversing the gap between resource-poor and resource-rich groups for volunteering with parties and voting
- …