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Title: FELIX-2.0: New version of the finite element solver for the time dependent generator coordinate method with the Gaussian overlap approximation

Journal Article · · Computer Physics Communications
ORCiD logo [1];  [2];  [2];  [3]
  1. Univ. Paris-Sud, Orsay (France). Inst. of Nuclear Physics. IN2P3-CNRS
  2. Alternative Energies and Atomic Energy Commission (CEA), Arpajon (France)
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Nuclear and Chemical Science Division
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The time-dependent generator coordinate method (TDGCM) is a powerful method to study the large amplitude collective motion of quantum many-body systems such as atomic nuclei. Under the Gaussian Overlap Approximation (GOA), the TDGCM leads to a local, time-dependent Schrödinger equation in a multi-dimensional collective space. In this study, we present the version 2.0 of the code FELIX that solves the collective Schrödinger equation in a finite element basis. This new version features: (i) the ability to solve a generalized TDGCM+GOA equation with a metric term in the collective Hamiltonian, (ii) support for new kinds of finite elements and different types of quadrature to compute the discretized Hamiltonian and overlap matrices, (iii) the possibility to leverage the spectral element scheme, (iv) an explicit Krylov approximation of the time propagator for time integration instead of the implicit Crank–Nicolson method implemented in the first version, (v) an entirely redesigned workflow. We benchmark this release on an analytic problem as well as on realistic two-dimensional calculations of the low-energy fission of 240Pu and 256Fm. Low to moderate numerical precision calculations are most efficiently performed with simplex elements with a degree 2 polynomial basis. Higher precision calculations should instead use the spectral element method with a degree 4 polynomial basis. Finally, we emphasize that in a realistic calculation of fission mass distributions of 240Pu, FELIX-2.0 is about 20 times faster than its previous release (within a numerical precision of a few percents).

Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Univ. Paris-Sud, Orsay (France)
Sponsoring Organization:
USDOE Office of Science (SC); USDOE
Grant/Contract Number:
AC52-07NA27344; AC05-00OR22725; AC02-05CH11231
OSTI ID:
1438682
Alternate ID(s):
OSTI ID: 1548986
Report Number(s):
LLNL-JRNL-735217; TRN: US1900485
Journal Information:
Computer Physics Communications, Vol. 225; ISSN 0010-4655
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

References (22)

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The generator coordinate method and quantised collective motion in nuclear systems journal January 1987
Microscopic analysis of collective dynamics in low energy fission journal October 1984
Time-dependent quantum collective dynamics applied to nuclear fission journal February 1991
Microscopic approach of fission dynamics applied to fragment kinetic energy and mass distributions in U 238 journal February 2005
Fission fragment charge and mass distributions in Pu 239 ( n , f ) in the adiabatic nuclear energy density functional theory journal May 2016
Fission dynamics of Cf 252 journal May 2017
Numerical search of discontinuities in self-consistent potential energy surfaces journal October 2012
FELIX-1.0: A finite element solver for the time dependent generator coordinate method with the Gaussian overlap approximation journal March 2016
The generator coordinate theory of collective motion journal November 1968
Local Gaussian Approximation in the Generator Coordinate Method journal February 1975
An extended gaussian overlap approximation in the generator coordinate method journal March 1985
Microscopic theory of nuclear fission: a review journal October 2016
Microscopic calculation of Pu 240 scission with a finite-range effective force journal November 2009
Three-dimensional alpha shapes journal January 1994
Finite element derivative interpolation recovery technique and superconvergence journal December 2011
FELIX-1.0: A finite element solver for the time dependent generator coordinate method with the Gaussian overlap approximation dataset January 2019
Microscopic calculation of 240Pu scission with a finite-range effective force text January 2009
FELIX-1.0: A finite element solver for the time dependent generator coordinate method with the Gaussian overlap approximation text January 2015
Fission fragment charge and mass distributions in 239Pu(n,f) in the adiabatic nuclear energy density functional theory text January 2016
Microscopic approach of fission dynamics applied to fragment kinetic energy and mass distributions in 238U text January 2005
FELIX-1.0: A finite element solver for the time dependent generator coordinate method with the Gaussian overlap approximation dataset January 2019

Cited By (3)

Microscopic self-consistent description of induced fission dynamics: finite temperature effects text January 2018
Fission of $^{240}$Pu with symmetry-restored density functional theory text January 2020
Microscopic Calculation of Fission Product Yields with Particle Number Projection text January 2021

Figures / Tables (15)

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Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
97 MATHEMATICS AND COMPUTING
FELIX
finite element
spectral element
generator coordinate method
Gaussian overlap approximation
nuclear fission