skip to main content

SciTech ConnectSciTech Connect

Title: Particle-in-cell modeling for MJ scale dense plasma focus with varied anode shape

Megajoule scale dense plasma focus (DPF) Z-pinches with deuterium gas fill are compact devices capable of producing 10{sup 12} neutrons per shot but past predictive models of large-scale DPF have not included kinetic effects such as ion beam formation or anomalous resistivity. We report on progress of developing a predictive DPF model by extending our 2D axisymmetric collisional kinetic particle-in-cell (PIC) simulations from the 4 kJ, 200 kA LLNL DPF to 1 MJ, 2 MA Gemini DPF using the PIC code LSP. These new simulations incorporate electrodes, an external pulsed-power driver circuit, and model the plasma from insulator lift-off through the pinch phase. To accommodate the vast range of relevant spatial and temporal scales involved in the Gemini DPF within the available computational resources, the simulations were performed using a new hybrid fluid-to-kinetic model. This new approach allows single simulations to begin in an electron/ion fluid mode from insulator lift-off through the 5-6 μs run-down of the 50+ cm anode, then transition to a fully kinetic PIC description during the run-in phase, when the current sheath is 2-3 mm from the central axis of the anode. Simulations are advanced through the final pinch phase using an adaptive variable time-step tomore » capture the fs and sub-mm scales of the kinetic instabilities involved in the ion beam formation and neutron production. Validation assessments are being performed using a variety of different anode shapes, comparing against experimental measurements of neutron yield, neutron anisotropy and ion beam production.« less
Authors:
; ;  [1] ;  [2] ; ;  [3]
  1. Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States)
  2. National Security Technologies, Las Vegas, NV 89030 (United States)
  3. Voss Scientific LLC, Albuquerque NM 87108 (United States)
Publication Date:
OSTI Identifier:
22390821
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1639; Journal Issue: 1; Conference: 9. International Conference on Dense Z Pinches, Napa, CA (United States), 3-7 Aug 2014; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ANISOTROPY; ANODES; AXIAL SYMMETRY; COMPARATIVE EVALUATIONS; DEUTERIUM; ELECTRONS; LAWRENCE LIVERMORE NATIONAL LABORATORY; NEUTRONS; PLASMA FOCUS; PLASMA FOCUS DEVICES; PLASMA INSTABILITY; PLASMA SHEATH; PLASMA SIMULATION; PULSES