Line Spectra

To compute the line spectrum of a single ion, one need do little more than specify a wavelength grid and the ion of interest:

    variable lo, hi, f, fe17_lines, s;

        %  Load the spectroscopy database

    plasma(aped);

        %  define a wavelength grid for the model spectrum

    (lo, hi) = linear_grid (1, 35, 8192);

        %  One way to define a multi-component spectral
        %  model is by using an array of structures.
        %  Here, we use a simple model with only one
        %  temperature component (see the advanced examples
        %  for details on computing more complicated models):

    s = default_plasma_state();
    define_model (s);

        %  To compute the contribution from Fe XVII lines
        %  alone, we first obtain a list of the Fe XVII lines...

    fe17_lines = where(el_ion(Fe,17));

        %  Then we compute the spectrum on the specified grid,
        %  using the MODEL_LINES keyword to specify that
        %  only line emission should be included:

    f = model_spectrum (lo, hi, MODEL_LINES, fe17_lines);

        %  Now, plot the result:

    variable id = plot_open ("ex_linespec.ps/cps");

    xlabel (latex2pg ("\\lambda" + " [\\A]"));
    ylabel ("Flux");
    title ("Fe XVII line spectrum");
    hplot (lo, hi, f);

    plot_close (id);