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Reverb Parameters

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Sam Mangham edited this page Jul 12, 2019 · 4 revisions

Reverb.type

Whether to perform reverberation mapping. Reverberation mapping tracks the path of photons emitted in the simulation as they travel through the geometry, assuming that any delays from recombination etc. are negligible and all delays are due to light travel time. For each final spectrum, all contributing photons are output to a '.delay_dump' file that can then be processed using our 'tfpy' Python (no relation) library.

Type

Enumerator

Values

  • none: Off

  • photon: Each photon is assigned an initial path based on its distance from the central source (assuming emission in the disk and wind is correlated with emission from the CO).

  • wind: CO photons are assigned paths as in Photon mode, disk photons are assigned paths as set by the reverb.disk_type parameter. Photons generated in the wind are assigned a path based on the distribution of paths of photons that have contributed to continuum absorption in that cell.

  • matom: This works as wind mode, but for a number of specified macro-atom lines paths are tracked for those photons who cause a deexcitation into a given line. When a photon is emitted in one of those lines, the path is drawn from that specific distribution. This distribution is build up not just from the last cycle of the simulation, but from all cycles after the wind achieves

    90% convergence. This is necessary as some lines are poorly-sampled.

    This mode gives pretty much identical results to wind mode, but at least we made it to check rather than just assuming it would be fine.

    This requires that Line_transfer is either macro_atoms or macro_atoms_thermal_trapping

File: setup_reverb.c

Reverb.matom_lines

Number of macro-atom lines to track paths for individually. This many reverb.matom_line entries are required, and the line associated with each has the path of photons deexciting into it recorded in its own array. Note: This doesn't give rise to any noticable differences to the pure wind mode in most simulations.

Type

Integer

Values

Greater than or equal to 0

Parent(s)

File: setup_reverb.c

Reverb.matom_line

Specifies a line associated with a given macro-atom transition. The species and transition involved are specified. The internal line associated with this transition will be printed to standard-out for use when processing outputs. A line is specified as Element:Ion:Upper level:Lower level.

Type

Int:Int:Int:Int

Values

0:>0:>1:>0

Parent(s)

File: setup_reverb.c

Reverb.filter_lines

Whether or not to filter any lines out of the output file. This is used to keep output file sizes down, and avoid them overwhelming the user.

Type

Int

Values

  • 0: No filtering

    Include all photons that contribute to the spectra in the output file. Not recommended as it leads to gargantuan file sizes.

  • -1: Filter continuum

    Include all photons whose last interaction was scatter or emission in a line. Recommended setting for exploratory runs where you'd like to identify which lines are the easiest to process.

  • N: Filter lines

    Include N Reverb.filter_line entries, each specifying one line to keep in the output file. If reverb.matom_lines is >0, all macro-atom lines of interest are automatically included in the filter list.

Parent(s)

File: setup_reverb.c

Reverb.filter_line

Line number of one line to include in the output .delay_dump file. This is the python internal line number. It can be found using either the macro-atom mode (which prints out the line number once it's found one) or by doing an exploratory run with reverb.filter_lines = -1, then looking through the delay dump file for photons of the right wavelength to see what their line is. This should almost certainly be changed to be specified using a species and wavelength!

Type

Integer

Values

Any valid line index

Parent(s)

File: setup_reverb.c

Reverb.path_bins

Number of bins for photon paths. Reverb modes that record the distribution of path lengths in every wind cell bin them in this number of bins. Bins are logarithmically spaced between the minimum scale in the system (the smallest 'minimum radius' in any domain) and the 10 * the maximum scale in the system (10 * the 'maximum radius' in any domain). Default value is 1000, going much higher does not lead to qualitative differences in TF, going lower makes the bin boundaries show up in the TF.

Type

Integer

Values

Greater than 0

Parent(s)

File: setup_reverb.c

Reverb.visualisation

Which type of visualisation to output, if any. Reverb modes that keep arrays of photon paths per cell can output them either as averages in a 3d model, or as a selection of flat text files with full bin-by-bin breakdowns. Useful for diagnostics.

Type

Enumerator

Values

  • none: No visualisation.

  • vtk: Mesh visualisation. Outputs mean incident path per cell, photon count per cell, and mean observed delay to '.vtk' format, readable using a range of programs including (my preferred option) VisIt, available at https://visit.llnl.gov/.

  • dump: Outputs distributions of paths for continuum heating and each line to a range of 'dump cells' specified by X & Z position.

  • both: Outputs both vtk and dump.

Parent(s)

File: setup_reverb.c

Reverb.dump_cells

Number of cells to dump. When dumping the path distribution info for a range of cells, this specifies the number of lines of Reverb.dump_cell that will be provided.

Type

Integer

Values

Greater than or equal to 0

Parent(s)

File: setup_reverb.c

Reverb.dump_cell

Position for a cell, listed as a pair of R:Z coordinates. Will accept any position that falls within a grid, will error out on ones that don't. This can be slightly awkward and you may want to run a quick test then use py_wind to idenfity where wind locations are.

Type

Float:Float

Unit

cm:cm

Values

0:>0

Parent(s)

File: setup_reverb.c

Reverb.angle_bins

Used when generating 3d .vtk output files for visualisation. Sets the number of angle bins used in the output. Aesthetic only; bigger makes prettier meshes with larger filesizes.

Type

Integer

Values

Greater than 0

Parent(s)

File: setup_reverb.c

Reverb.disk_type

Setting for how photons generated in the disk are treated when generating path distributions for wind cells.

Type

Enumerator

Values

  • correlated: This mode assumes that disk emission is correlated with the central source. Photons generated in the disk start with a delay equal to the direct distance to the central source. This assumes that the ionisation state and luminosity of the disk surface layer is mostly determined by unscattered photons from the central source.

  • uncorrelated: This mode generates photons with a delay of 0 wherever in the disk they come from. This mode is of slightly questionable use and should be ignored in preference to 0 or 2. It will, in practise, generally work out similar to type 0 as most of the UV photons are generated close-in to the CO.

  • ignore: This mode assumes that disk photons do not correlate with the central source (i.e. disk surface ionisation state and emissivity is driven not by irradiation from the CO but by the mass inflow). This means that whilst they contribute to heating the wind, they do not strongly contribute to the lags for a given line. Photons generated by the disk do not contribute to the path distributions in the wind in this mode.

    By removing the (generally) short-delay disk photons from the wind path distributions, this will slightly bias them towards the longer delays associated with wind self-heating/excitation.

Parent(s)

File: setup_reverb.c

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