Sample Problem: Cylindrical Halfraum at NIF

Setting Up the Grid

Perform the following steps to set up a cylindrical halfraum. Set the orientation such that the beams enter the LEH at roughly equal entrance angles.

• Select Target | Add Object.
• Select "Cylindrical Halfraum" for the target component type.
• Set the object name to "Halfraum".
• In the Position tab of the Object Parameters Dialog:
• For the Reference Coordinate System, use "Target Chamber".
• Use the default object position: r = (0,0,0). That is, put the centroid of the halfraum at target chamber center.
• Find the port locations for the drive beams:
  • View the laser port positions by selecting View | Port Positions.
  • The mean angles to the Q46T beams is approximately: polar = 50 degrees; azimuthal = 129 degrees.
  • The mean angles to the Q46B beams is approximately: polar = 130 degrees; azimuthal = 140 degrees.
  • So let's point the LEH at angles: polar = 90 degrees; azimuthal = 135 degrees.
• Enter the angles for the polar and azimuthal orientation angles (90 and 135 degrees, respectively).
• In the Size/Gridding tab of the Object Parameters Dialog:
  • Set the radius to 0.08 cm (800 microns).
  • Set the length to 0.12 cm, and LEH radius to 0.06 cm.
  • (For all pre-configured hohlraums, surface normals face inward.)
  • Use 16 grid points along the Z-axis.
  • Set the number of azimuthal grid points to 18 (20 degrees per node).
  • For the top disk (LEH side) of the hohlraum, use 4 radial grid points. For the bottom, use 10 radial grid points.
• Select "OK". (The halfraum is added to the graph frame.)