This section configures the neutral diagnostic settings and is optional. If not present, the code will not do any neutral diagnostics. It accepts the following data:

  • reports(:), character(*), default = “-“
  • ndump_fac, integer, default = 0
  • ndump_fac_ave, integer, default = 0
  • ndump_fac_lineout, integer, default = 0
  • n_tavg, integer, default = -1
  • n_ave(x_dim), integer, default = -1
  • prec, integer, default = 4

reports - specifies the grid quantities to report, including spatial/time averaging, lineouts, etc., as described in the grid diagnostics section. The available quantities are:

  • “ion_charge” - Background ion charge density (particle density times ionization level)
  • “neut_den” - Density of the initial background neutral gas

ndump_fac - controls the frequency of full grid diagnostics. This value is multiplied by the ndump value specified in the time_step section to determine the number of iterations between each diagnostic dump. If set to 0, the writing of this diagnostic information is disabled.

ndump_fac_ave - controls the frequency of spatial average / envelope grid diagnostics. This value is multiplied by the ndump value specified in the time_step section to determine the number of iterations between each diagnostic dump. If set to 0, the writing of this diagnostic information is disabled.

ndump_fac_lineout - controls the frequency of lineout / slice diagnostics. This value is multiplied by the ndump value specified in the time_step section to determine the number of iterations between each diagnostic dump. If set to 0, the writing of this diagnostic information is disabled.

n_tavg - specifies the number of time steps to be used when calculating the time averaged diagnostics. The frequency of these diagnostics is controlled by the ndump_fac parameter described above.

n_ave - number of gridpoints on each direction to average over for spatially averaged dumps. The frequency of these diagnostics is controlled by the ndump_fac_ave parameter described above.

prec - controls the numerical precision used for grid diagnostics. The default is to save data in single precision (prec = 4). If the user wants data to be saved in double precision, this parameter must be set to

  1. This option is ignored if OSIRIS is compiled in single precision.

Here’s an example of a diag_neutral section that will write diagnostics information every 20*ndump iterations for ion charge density.

diag_neutral
{
  ndump_fac = 20,
  reports = "ion_charge",
}