Sample Problem: NIF Unconverted Light in 3ω Focus Plane

Setting Laser Beam Parameters

In this example, we set the beam parameters as follows:

• Point the beams at the center of the rectangle (i.e., at target chamber center)
• Set all beams powers to 2.5 TW.

It is often useful to group the beams in each problem into clusters. For this problem, we set all beams of quads Q15T into a cluster called "Beams_Quad_15". To do this,

• Select Lasers | Add Cluster. Give the name "Beams_Quad_15".
• Select beams from Quad Q15T (beams A, B, C, D). With all 4 beams highlighted, use the right mouse button, and select Move To Cluster | Beams_Quad_15. (This can also be accomplished using the menu: Lasers | Move To Cluster | Beams_Quad_15.)

To set the beam power for all drive beams:

• Right-click on cluster "Beams_Quad_15", and select Set Powers.
• Set the power to 2.5 TW. This represents the total power in the blue, green, and red cones for NIF.

To point the beams:

• Right-click on cluster "Beams_Quad_15", and select Set Pointing.
• For reference coordinate system, use: "Target Chamber".
• Set the position of the Reference Point for Beam Pointing to: r = (0, 0, 0) cm. This points the beams at target chamber center.

The number of beamlets per laser beam can be adjusted by selecting: Lasers | Beam Profile. For this problem, set the number of beamlets per beam to 1000. Use a "Uniform" spatial beam profile.

All laser beams are now set up. The image below shows the rectangle viewed from (in spherical coordinates):

• polar angle = 23.5 degrees
• azimuthal angle = 78.75 degrees
• radius = 4 cm

See setting the viewing position to adjust the viewing location.