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| -rw-r--r-- | Docs/source/running_cpp/parameters.rst | 19 |
1 files changed, 10 insertions, 9 deletions
diff --git a/Docs/source/running_cpp/parameters.rst b/Docs/source/running_cpp/parameters.rst index b71c44c93..a1e205d55 100644 --- a/Docs/source/running_cpp/parameters.rst +++ b/Docs/source/running_cpp/parameters.rst @@ -921,27 +921,28 @@ Collision initialization WarpX provides a relativistic elastic Monte Carlo binary collision model, following the algorithm given by `Perez et al. (Phys. Plasmas 19, 083104, 2012) <https://doi.org/10.1063/1.4742167>`_. -* ``collisions.ncollisions`` (`int`) optional (default `0`) - Number of collision types. - * ``collisions.collision_names`` (`strings`, separated by spaces) - The name of each collision type. It must be provided if ``collisions.ncollisions`` is not zero. + The name of each collision type. This is then used in the rest of the input deck; in this documentation we use ``<collision_name>`` as a placeholder. - The number of strings provided should match the number of collision types, - i.e. ``collisions.ncollisions``. * ``<collision_name>.species`` (`strings`, two species names separated by spaces) The names of two species, between which the collision will be considered. - It must be provided if ``collisions.ncollisions`` is not zero, and - the number of provided ``<collision_name>.species`` should match - the number of collision types, i.e. ``collisions.ncollisions``. + The number of provided ``<collision_name>.species`` should match + the number of collision names, i.e. ``collisions.collision_names``. * ``<collision_name>.CoulombLog`` (`float`) optional A provided fixed Coulomb logarithm of the collision type ``<collision_name>``. + For example, a typical Coulomb logarithm has a form of + :math:`\ln(\lambda_D/R)`, + where :math:`\lambda_D` is the Debye length, + :math:`R\approx1.4A^{1/3}` is the effective Coulombic radius of the nucleus, + :math:`A` is the mass number. If this is not provided, or if a non-positive value is provided, a Coulomb logarithm will be computed automatically according to the algorithm. + a Coulomb logarithm will be computed automatically according to the algorithm in + `Perez et al. (Phys. Plasmas 19, 083104, 2012) <https://doi.org/10.1063/1.4742167>`_. .. _running-cpp-parameters-numerics: |