Laser Beam Power Sources

Supported Laser Systems:

VISRAD currently supports the following laser beam systems:

• OMEGA
• OMEGA-EP
• NIF
• ORION
• LMJ
• MTW
• Systems with Custom (user-defined) Laser Beams

The OMEGA, OMEGA-EP, NIF, ORION, and MTW systems include both the laser beam ports and diagnostic ports.

Laser Beam Properties:

Details discussing laser beam properties, and how to set them, are in:

• Grouping beams into clusters
• Turning beams on and off
• Showing and hiding beams
• Laser Beam List (in main window)
• Laser Beam Parameters Dialog
• Setting up Custom Laser Beams
• NIF Beam Parameters Dialog (for unconverted laser light)

Note that in selecting and setting up laser beams, it is often useful to view the laser port positions using the Port Positions Dialog. This provides a convenient way to view the angles to each laser port, using the coordinate system of any of the target components. Using this, the entrance angle of a beam into a hohlraum or the angle at which a beam hits a backlighter is readily determined.

A table summarizing parameters for all laser beams can be also be viewed in a separate window. To view this, select View | Laser Beams Summary.

Overlays of laser beam spots (i.e., beam-target intersection points) can also be displayed in the main window.

Computing the Incident Laser Power on Surface Elements

The laser deposition calculation can be done using either the "Standard" grid set up for each target component, or use an Adaptive Mesh Refinement (AMR) grid. When computing the laser intensity distribution using AMR modeling, the target grid is automatically sub-divided into a submesh using triangular elements at locations hit by the laser beams.

Aspects of the AMR modeling include:

• To view the laser intensity using AMR mesh, select Display | Direct Laser Power Deposited | AMR Grid.
• Parameters used in controlling the grid subdivision can be set in the Preferences dialog.
• The AMR intensities within the subgrid of a surface element are displayed in the VISRAD Main Graphics Window. The AMR incident laser intensity results for the sub-grid elements are summed for each surface element and used in:
  • Radiation flux calculations.
  • Results shown in the Surface Elements Table.
• At AMR subgrid level:
  • Picking to get individual surface element data (using the button) is supported. Except for Incident Laser Intensity, all quantities in the Surface Element Parameters dialog refer to standard grid values.
• Results at the ARM subgrid level are not saved to a workspace.

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