Effect of P2 shields on DANTE view of hohlraums

The beam pointing is "nominal" - i.e. 15 Cone 2 and Cone 3 beams on each side of the hohlraum, pointed and focused at the LEH center, thus producing two rings. Power is constant at 500 GW/beam for 1 ns.

These hohlraums are longer than the ones we've been modeling: 2500 μm. But they're the same 1600 μm diameter with three-quarter LEHs (1200 μm diameter). This model is based on Fig. 1 of Amendt et al., PRL, 77, 3815 (1996). For the simulations with shields, the shields are 600 μm in diameter (50% LEH diameter) and are +/-600 μm from the hohlraum midplane. They have identical material properties (i.e. albedo) as the hohlraum barrel (this might overestimate the albedo and thus the temperature a bit, since that albedo model is explicitly time-dependent and not temperature dependent).

These are the DANTE-views of the standard hohlraum (left) and the hohlraum with two shields (right). The color emission temperature scales are identical, and the same as usual (blue=140eV, red=220eV).

The columns labeled "sample" refer to the usual sample mounted on the barrel wall at the midplane, with those labeled "sample@TCC" refer to a second sample, at target chamber center (and hohlraum center), facing one of the LEHs (or shields, as the case may be).

Below we show a different view of the same two simulations. This view is from the hohlraum axis, 500 μm beyond the midplane, looking at the LEH (or shield).

The small item in the middle of the view on the left is the tiny sample at TCC, seen from the back. On the right, it can be seen that the shield is quite uniformly heated to a relatively low (but not very low) temperature (roughly 162 eV).

Finally, note that with the shields, the DANTE temperature is lowered, as the back, cool side of the shield has a significant view factor. Coincidentally, the DANTE temperatures are very similar to that on the sample at TCC (see the table above). The back of the shield has a temperature of about 150 eV (compared to roughly 190 eV for barrel wall areas whose views are projected near the edge of the shield - please let me know if you'd like a demo version of the view-factor code to play around with so you can check the temperatures of various surfaces). Below we show a temperature map with a restricted temperature range, showing the temperature of the back of the shield and the gradient across the shield.

The color scale here goes only from 148eV to 155eV.

All snapshots shown here are DANTE-view at 1 ns.

*These values differ slightly from, e.g. those from the empty hohlraum in the capsule study, because this hohlraum is slightly longer than in our other simulations.