John Santarius and Greg Moses

University of Wisconsin

HAPL Project Meeting

PPPLDecember 12-13, 2006

Effects of Long Mean-Free-PathIons on Shock Breakout

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Ghost zone

Hydro zone

Hydro zone

Hydro zone

Ghost zone

Hydro zone

Hydro zone

Hydro zone

Null zone

Ghost zone

Hydro zone

Hydro zone

Hydro zone

Null zone

Ghost zone

Hydro zone

Hydro zone

Hydro zone

Gap between hydro zones has closed; zones get

renumbered.

In original conception, ghost zone pushed hydro zones apart; absorption

can also occur.

In the Original Conceptual Picture, Long Mean-Free Path “Ghost” Zones Move through Hydro Zones

• Ghost zones transfer momentum with those hydro zones through which they pass.

Ghost zone

Hydro zone

Hydro zone

Hydro zone

Ghost zones now get renumbered.

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Zel’dovich & Raizer Shock-Breakout ProblemChosen for Code Development

• Zel’dovich & Raizer, Physics of Shock Waves and High-Temperature Hydrodynamic Phenomena, Chapter 25.

• Strong, spherical shock propagating through an exponentially falling density gradient. Analogous to ICF shock propagating through the blow-off plasma.

• Initial velocities equal zero; mass density and temperature shown below.

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For Pure Hydro Motion,Velocities Get Unphysically High

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Gap (Null Zone) between Hydro ZonesFills Quickly because of Internal Pressure

Hydro zones about to merge

• Ghost zones drag hydro zones upward in energy (and velocity).

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Slowest Ghost Zone Fades after a Short Time

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After a Short Time,Ghost Zones Nearly Free-Stream

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Status and Summary

• Mathematica® code appears to move hydro and long mean-free path (ghost) zones properly for the simple Zel’dovich and Raizer test case.

• Momentum transfer between zones also appears to be working.

• A minor zone renumbering problem remains to be addressed.

• Next step is to use initial conditions from a HAPL test problem.

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Reserve Slides

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DTCore

rshock (cm) < 0.001

rshock (cm) < 0.001

vshock (cm/s) 6.6 x 106

ni (cm-3) 1.5 x 1026

Ti (keV) 276

Te (keV) 72

Ave. charge state 1

rshock / mfp > 1000

DTCore

DT-CHShock

rshock (cm) < 0.001 0.026

rshock (cm) < 0.001 0.02

vshock (cm/s) 6.6 x 106 5.5 x 108

ni (cm-3) 1.5 x 1026 5.1 x 1024

Ti (keV) 276 86

Te (keV) 72 47

Ave. charge state 1DT 1CH 1

rshock / mfp > 1000 1.1

DTCore

DT-CHShock

CH-AuShock

rshock (cm) < 0.001 0.026 1.1

rshock (cm) < 0.001 0.02 0.004

vshock (cm/s) 6.6 x 106 5.5 x 108 8.6 x 107

ni (cm-3) 1.5 x 1026 5.1 x 1024 5.0 x 1018

Ti (keV) 276 86 2.8

Te (keV) 72 47 0.69

Ave. charge state 1DT 1CH 1

CH 1Au 36

rshock / mfp > 1000 1.1 0.001

At 34.592 ns, the DT-CH Shock Thickness andIncoming Ion Mean Free Paths Become Comparable

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Qualitative Motion of Ghost and Hydro Zones Appears Reasonable