Effect of LEH shields on DANTE view of hohlraums

2300 μm long 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.

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.

All snapshots shown here are at 1 ns.

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).