SpectraPLOT: Drilldown Plots

Drilldown Plots show a variety of depth-dependent physical and optical properties for a given line-of-sight (i.e., a ray that extends from the detector plane through the plasma grid).

The reason that Drilldown Plots are useful is that the intensity for a pixel in the detector image plane is computed by solving the radiative transfer equation along that line-of-sight. Therefore, these plots can be used to gain an understanding of what processes affect the detector image intensities.

To display drilldown plots, click on the Drilldown toolbutton on the toolbar, and select a detector pixel in an Image plot window (below left). When this is done, the Drilldown Plot Selection dialog is display (below right).

The parameters listed at the top of the selection dialog correspond to those of the selected pixel in the Image plot window.

Note that because the Drilldown plots show data for a particular simulation time, this option is not available when the Image plot item uses Time-Integrated time settings.

A variety of parameters can be displayed as a function of depth (in cm or areal mass density in g/cm²). These include:

• Temperature
• Mass, electron, and ion densities
  • Mass densities are shown for each material in the plasma
• Mean ion charge
• Ionization fractions
  • Ionization fractions for each atomic element (curves are not displayed if fractions are very small)
• Atomic level populations
  • Shown for selected levels, or all levels of selected ions (in cases where a large number of levels are selected, the number of line plots may be limited)
• Specific intensity (I_ν) and optical depth (τ_ν)
  • The intensity and optical depth are shown for each of the extra photon energies specified in the Photon Energies tab of the SPECT3D Output.

Note that Depth is measured from the point at which the line-of-sight intersects that plasma grid on the detector side of the plasma. Depth-dependent quantities are zone-centered and are shown as histograms.

Optical depth is also integrated from the detector side of the plasma.

Specific intensities are computed by solving the transport equation, starting from the back of the plasma (away from the detector side). At the back of the plasma, the specific intensity is zero, unless there is a non-zero boundary condition (as in the case of using a Backlighter).

Frequency-dependent specific intensity and optical depth plots can also be shown for the selected Image pixel. The intensities correspond to the values at the detector image plane. The optical depths are the values integrated along the line-of-sight through the entire plasma grid.

For some SPECT3D simulations, ionization fraction and/or level population data are not available.

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