Dust charge chemistry

It is also possible to include the dust grains as chemical species, and calculate the charging of grains. For the various setups see examples/Processes/GrainCharges and the README file.

Dust charge moments method

The currently recommended setup to activate charge chemistry is

------ dust charge parameters ------
.true.      ! dust_charge_chemistry    ! activate dust charge chemistry
.true.      ! charge_chemistry_v3      ! activate the moment method for the chemical rates
5000        ! Zmax_v2                  ! max/min charge of one grain
.true.      ! check_network            ! is required to generate all the charge exchange reactions

Please note that the dust grains need to be included in Elements.in as Z and in Species.in as chemical species Z,Z+,Z- (see examples/Processes/GrainCharges/GrainCharges_v3).

With the check_network switch ProDiMo check if actually all required reactions are included in the network, if not it will generate them. Those generated reactions need to be added to the chemical network for the particular model (see also Generate charge exchange Reactions).

For details on the implementation of this method see Balduin+ (2023) Appendix C.

Individual charge states

Whit the following setups for the charge chemistry

------ dust charge parameters ------
.true.      ! dust_charge_chemistry    ! activate dust charge chemistry
.true.      ! check_network            ! is required to generate all the charge exchange reactions

one chan trace individual charges. Differently to the moments method, each charge states has its one chemical reactions. However, this can become computationally expensive, therefore the max/min charges are currently limited to 6.

Also here Z has to be included in Elements.in and Species.in, where at least Z,Z+,Z- need to be present and additionally higher charge states e.g. Z++ and Z--.

Further details on this kind of charge chemistry can be found in Thi+ (2019).

Example setups are examples/Processes/GrainCharges/GrainCharges_v1 and examples/Processes/GrainCharges/GrainCharges_v2, where the first one includes only Z,Z+,Z- as species and the second example also includes higher charge states.

Please note this method should give the same results as the charge moment method if the maximum and minumum charges are the same in both setups. So for example Zmax_v2 = 6 for charge_chemistry_v3, and included species upt to Z------ and Z++++++

Size dependent charge chemistry

This is the most complex method and is described in Balduin+ (2023), the example Setup can be found here examples/Processes/GrainCharges/GrainCharges_v3_dustbins.