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View factor estimation of hot spot velocities in inertial confinement fusion implosions at the National Ignition Facility.
- Source :
- Physics of Plasmas; Aug2020, Vol. 27 Issue 8, p1-17, 17p
- Publication Year :
- 2020
-
Abstract
- Inertial confinement fusion (ICF) experiments at the National Ignition Facility suffer from asymmetries in the x-ray drive, which degrade capsule performance compared to expectations for a symmetric one-dimensional implosion. Mode 1, or pole-to-pole, drive asymmetry can reduce confinement and implosion efficiency, driving a bulk motion of the hot spot that is detectable by neutron diagnostics. Understanding and removing sources of mode 1 asymmetry in ICF implosions is important for improving performance, and the three-dimensional nature of the problem makes high-resolution radiation-hydrodynamic modeling extremely computationally expensive. This work describes a reduced order view factor model that calculates the drive asymmetry induced by beam-to-beam variations in laser delivery and Hohlraum diagnostic windows along the equator. The capsule response is estimated by coupling to a Green's function that relates final hot spot velocity to the applied time-varying mode 1 asymmetry. The model makes several predictions about the impact of mode 1 drivers such as laser delivery and target misalignment and achieves good agreement in both the magnitude and the vector direction for several shots in three families of high-performance platforms. However, notable discrepancies suggest that other potential sources of mode 1 asymmetry not captured by the model are also at play. [ABSTRACT FROM AUTHOR]
- Subjects :
- INERTIAL confinement fusion
GREEN'S functions
VELOCITY
Subjects
Details
- Language :
- English
- ISSN :
- 1070664X
- Volume :
- 27
- Issue :
- 8
- Database :
- Complementary Index
- Journal :
- Physics of Plasmas
- Publication Type :
- Academic Journal
- Accession number :
- 145434782
- Full Text :
- https://doi.org/10.1063/5.0009746