Update documentation on particle initialization

1 files changed, 39 insertions, 2 deletions

diff --git a/Docs/source/running_cpp/parameters.rst b/Docs/source/running_cpp/parameters.rst
index 2d4f0f874..540389f0f 100644
--- a/Docs/source/running_cpp/parameters.rst
+++ b/Docs/source/running_cpp/parameters.rst
@@ -90,6 +90,42 @@ Distribution across MPI ranks and parallelization
 Particle initialization
 -----------------------
 
+* ``particles.nspecies`` (`int`)
+    The number of species that will be used in the simulation.
+
+* ``particles.species_names`` (`strings`, separated by spaces)
+    The name of each species. This is then used in the rest of the input deck ;
+    in this documentation we use `<species_name>` as a placeholder.
+
+* ``<species_name>.charge`` (`float`)
+    The charge of one `physical` particle of this species.
+
+* ``<species_name>.mass`` (`float`)
+    The mass of one `physical` particle of this species.
+
+* ``<species_name>.injection_style`` (`string`)
+    Determines how the particles will be injected in the simulation.
+    The options are:
+
+    * ``NUniformPerCell``: injection with a fixed number of particles
+    per cell, with particles being evenly-spaced in each direction within a cell.
+    This requires the additional parameter ``<species_name>.num_particles_per_cell_each_dim``.
+
+    * ``NRandomPerCell``: injection with a fixed number of particles
+    per cell, with particles being randomly distributed within each cell.
+    This requires the additional parameter ``<species_name>.num_particles_per_cell``.
+
+    * ``Gaussian_Beam``:
+
+Additional parameters for plasma injection (``NUniformPerCell`` and ``NRandomPerCell``)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+
+Additional parameters for gaussian beams (``Gaussian_Beam``)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+
+
 Laser initialization
 --------------------
 
@@ -212,8 +248,9 @@ Numerics and algorithms
 -----------------------
 
 * ``warpx.cfl`` (`float`)
-    The ratio between the time step to be used in the simulation and
-    the CFL limit of the Maxwell solver.
+    The ratio between the actual timestep that is used in the simulation
+    and the CFL limit. (e.g. for `warpx.cfl=1`, the timestep will be
+    exactly equal to the CFL limit.)
 
 * ``warpx.use_filter`` (`0 or 1`)
     Whether to smooth the charge and currents on the mesh, after depositing