Materials Setup

SPECT3D materials are modeled using two approaches:

• DCA (Detailed Configuration Accounting)
  • Atomic energy levels and transitions of each atomic element are tracked explicitly.
  • LTE or non-LTE populations of atomic energy levels can be computed, and their calculation can include effects of a variety of processes (external radiation fields, non-Maxwellian electron distributions, ...).
  • Radiative properties of transitions are based upon computed atomic level populations.
  • High-resolution spectra can be computed, where individual lines are clearly resolved.
  • Very flexible, but more CPU-intensive.
  • More suitable for relatively low-Z elements (i.e., elements with fewer bound electrons).
• Non-DCA (or table look-up)
  • Atomic energy levels and transitions are not tracked explicitly.
  • Frequency-dependent emission and absorption properties are obtained from pre-computed tabular data files, and individual lines tend not to be well-resolved.
  • Atomic level populations used in generating tabular radiative data files may be either LTE or non-LTE, but in the non-LTE case non-local (i.e., photoionization and photoexcitation) effects are ignored.
  • Less flexible, but requires less CPU.
  • More suitable for relatively high-Z elements.

DCA materials consist of one or more atomic elements. For non-DCA materials, pre-computed tabular data are based on plasmas containing one or more atomic elements, but the elements in non-DCA materials are not treated explicitly in SPECT3D simulations.

For non-DCA materials, SPECT3D supports the use of PROPACEOS opacity data files.

A multi-material SPECT3D simulation may consist of a mix of DCA and non-DCA materials.

Setting Material Properties

The Materials setup widget is used to set up each of the SPECT3D materials for a simulation. A list of materials is shown in the box at the top of the widget. Materials can be added, deleted, or duplicated by pressing one of the buttons at the right of the box.

The parameters of individual materials are shown in the lower portion of the setup widget. To display and edit parameters for a particular material, click on the material in the box at the top.

When a new material is added, it is given a default name, which can be edited.

For a SPECT3D simulation utilizing a hydrocode data file to specify plasma properties, the SPECT3D material must be mapped to the appropriate variable name from the hydrocode file that is used to define the fractional abundance of that material in each cell (e.g., see hydro dataset file material fractions). Each SPECT3D material must be mapped to a unique hydrocode file variable name, and each hydrocode file variable name must be associated with a SPECT3D material.

Enter the mean atomic weight of the material. This, along with the mass density, is used to compute the total number of atoms for each atomic species in each volume element.

Select the Material Type: DCA or non-DCA.

• DCA materials consist of one or more atomic elements. Atomic elements are added or deleted by clicking the corresponding button on the right. When adding an element, simply select the element from the periodic table that appears. The number fraction of each element can be adjusted by either double-clicking on the element in the DCA list box, or by selecting the element and clicking the Set Fraction button.

• Non-DCA materials utilize tabular opacity data files. An opacity file must be specified for each non-DCA material. The file can be chosen either from the default PROPACEOS library location specified in Preferences or from a custom location.

Alternatively, a constant value for the opacity can be specified by checking the Use constant opacity check box. In either case, a constant multiplier can be applied by checking the Use opacity multiplier check box.

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