Effective thermal conductivity divided by SH thermal conductivity. OSHUN VFP calculations are: blue diamonds—Z = 1 (a), orange squares—Z = 2 (b), green triangle—Z = 4 (c). One hundred simulations have been run for the DUED-SNB model and for the DUED-CMG model. DUED-SNB is plotted with a solid blue line, DUED-CMG is plotted with a solid red line. The three panels compare the VFP results against DUED-SNB and DUED-CMG for Z = 1 in (a), for Z = 2 in (b), and for Z = 4 in (c).
(a) Effective thermal conductivity divided by SH thermal conductivity, blue diamonds: VFP-OSHUN Z = 1, solid lines: sharp cutoff flux limiters. (b) Effective thermal conductivity divided by SH thermal conductivity, blue diamonds: VFP-OSHUN Z = 1, green triangles: VFP-OSHUN Z = 4, blue solid line: sharp cutoff f = 0.02 Z = 1, cyan solid line: harmonic mean f = 0.04 Z = 1, green solid line: sharp cutoff f = 0.02 Z = 4.
Hot spot relaxation test. Non-local electron conduction SNB-CMG models are compared against VFP simulations (OSHUN), classical SH diffusive operator and SH flux limited with f = 0.08. Two representative instants have been chosen: 2 and 30 , the first is representative of a fully kinetic behavior, the second of a fluid-like regime. First line: temperature profile in linear scale. Second line: normalized temperature profile in logarithmic scale to highlight the formation of non-local electron tails. Third line: heat fluxes, fourth line: electric fields.
(a) Heat flux comparison at 30 . Green line: heat flux calculated with the VFP code OSHUN, red dashed line: heat flux calculated with the flux limiter technique f = 0.08. (b) displays on the same graph the heat flux and the corresponding temperature profile at 30 .
DUED-SNB and DUED-CMG comparison. The two non-local electron conduction models are compared at nanosecond timescales for a simplified temperature-density profile that should mock up an ICF scenario. Frame (a) compares temperature profiles at 4.3 ns, frame (b) at 4.7 ns. The image highlights how the electrons penetrate through the cold dense shell, thus, how the thermal front is treated ahead of the shock. DUED-SNB exhibits a much heavier precursor. Domain reduced to 700 μm for sake of clarity.
Boundary condition problem. Temperature profile and flux comparison for the SNB-CMG-SH-flux limited 0.08 thermal conduction models. Density ramps linearly from 1 g/cm3 at 0 cm to at 0.1 cm. Images displays temperatures (both in linear and logarithmic scales) and the flux only up to 0.06 cm for sake of clarity.
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