NLTE correction

NLTE correction#

The non-Local Thermal Equilibrium (NLTE) correction can be applied to the spectrum by setting the nlte attribute of the SME structure, before synthesize_spectrum or solve:

sme.nlte.set_nlte(el) # such as "Ca"
# Or provide your own grid:
sme.nlte.set_nlte(el, "path_to_your_grid")

The current elements with NLTE correction includes:

Warning

  • Long format VALD linelist is required for NLTE calculations. If only a short format has been given, then the calculations will only be in LTE. (See Linelist)

  • The NLTE grids are only compatible with the MARCS model atmosphere.

Note

Upon the first use of the NLTE correction, the NLTE grid will be downloaded from the server and this may takes a while, depending on the size of the NLTE grid.

Similarly they can be disabled for each element using sme.nlte.remove_nlte(el).

More details on NLTE can be found in the concept section.

Note

PySME also contains an experimental profile-based NLTE correction interface. This is separate from the standard sme.nlte departure-coefficient workflow and is documented in Profile-Based NLTE Corrections (Experimental).