Author: Vay, J.-L.
Paper Title Page
Modeling and Evaluation Thermionic Energy Converters in the Space-Charge Limit  
  • N.M. Cook, J.P. Edelen, C.C. Hall, Y. Hu, M.V. Keilman, P. Moeller, R. Nagler
    RadiaSoft LLC, Boulder, Colorado, USA
  • J.-L. Vay
    LBNL, Berkeley, California, USA
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC0017162.
Thermionic energy converters (TECs) are a promising technology for modular, efficient thermoelectric energy transfer. A TEC is comprised of a narrowly-separated cathode and anode, thermionic emission at the cathode drives a current across the gap which may generate electrical power. For high operating temperatures and large gap distances, currents can meet or exceed the Child-Langmuir limit. The steady-state operation of a TEC depends upon the emission characteristics of the cathode and anode, the presence of intra-gap electrodes, and the self-consistent transport of the electrons in the gap, for which high fidelity simulations with self-consistent emission models and complex boundary interactions are required. We present results from simulations of TECs using the Warp code, developed at Lawrence Berkeley National Lab. We demonstrate newly developed tools to accurately model a broad array of devices, including mesh refinement and cut-cell techniques for improved resolution, Schottky emission from shaped emitter surfaces, and CAD I/O for grid design and optimization. These tools are employed to validate and optimize realistic device designs for future energy applications.
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WEPLE02 Integrated Accelerator Simulation with Electromagnetics and Beam Physics Codes 885
  • L. Ge, Z. Li, C.-K. Ng, L. Xiao
    SLAC, Menlo Park, California, USA
  • D.A. Bizzozero, J. Qiang, J.-L. Vay
    LBNL, Berkeley, California, USA
  • D.P. Grote
    LLNL, Livermore, California, USA
  Funding: Work supported by US Department of Energy under contracts AC02-76SF00515, DE-AC02-05CH11231 and DE-AC52-07NA27344. Used resources of the National Energy Research Scientific Computing Center.
This paper presents an integrated simulation capability for accelerators including electromagnetic field and beam dynamics effects. The integrated codes include the parallel finite-element code suite ACE3P for electromagnetic field calculation of beamline components, the parallel particle-in-cell (PIC) code IMPACT for beamline particle tracking with space-charge effects, and the parallel self-consistent PIC code Warp for beam and plasma simulations. The common data format OpenPMD has been adopted for efficient field and particle I/O data transfer between codes. One application is to employ ACE3P and IMPACT for studying beam qualities in accelerator beamlines. Another is to combine ACE3P and Warp for investigating plasma processing for operational performance of RF cavities. A module for mapping the CAD geometry used in ACE3P to Warp Cartesian grid representation has been developed. Furthermore, a workflow has been implemented that enables the execution of integrated simulation on HPC systems. Examples for simulation of the LCLS-II injector using ACE3P-IMPACT and plasma ignition in SRF cavities using ACE3P-Warp will be presented.
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About • paper received ※ 20 August 2019       paper accepted ※ 19 November 2019       issue date ※ 08 October 2019  
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