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Fisher, P. F.

Paper Title Page
THPMN089 Enhancement of Heat Removal using Concave Liquid Metal Targets for High-Power Accelerators 2915
  • I. Konkashbaev, P. F. Fisher, A. Hassanein
    ANL, Argonne, Illinois
  • N. V. Mokhov
    Fermilab, Batavia, Illinois
  The need is increasing for development of high power targets and beam dump areas for the production of intense beams of secondary particles (IFMIF, SNS, RIA, LHC). The severe constraints arising from a MW beam power deposited on targets and absorbers, call for non-trivial procedures to dilute the beam. This study describes the development of targets and absorbers and the advantages of using flowing liquid metal in concave channels first proposed by IFMIF to raise the liquid metal boiling point by increasing the pressure in liquid supported by a centrifugal force. Such flow with a back-wall is subject to the Taylor-Couette instability. The instability can play a positive role of increasing the heat transfer from the hottest region in the target/absorber to the back-wall cooled by water. At the laminar stage of the instability with a certain wave number of vortexes, the heat transfer from a chain of vortexes to the wall increases heat removal by enhancing the convective transport inside the liquid bulk and from the bulk to the wall. Results of theoretical analysis and numerical modeling of both targets and dump areas for the IFMIF, ILC, and RIA facilities are presented.  
THPAN091 Spectral-Element Discontinuous Galerkin Simulations for Wake Potential Calculations: NEKCEM 3435
  • M. Min, Y.-C. Chae, P. F. Fisher
    ANL, Argonne, Illinois
  The demand for short bunches of 1 ps or less poses not only technical challenges in order to deliver the beams for leading-edge research but also poses computational challenges when it comes to investigating bunched multi-particle beam dynamics in order to improve the beam quality. We introduce a powerful high-order numerical tool based on spetral-element discretizations with discontinuous Galerkin approximation approach, which includes spectral element time domain solver for Maxwell's equation and electrostatic Poisson solver. We will demonstrate 3D simulations for wakefield and wake potential calculations in conducting cavity structures, as well as meshing and visualization components. We will discuss the overcome of the computational bottleneck by widely-used low-order finite difference programs for calculating wake field excited by 1-ps bunches, provided with performance and accuracy comparison.