doc

Docs/source/usage/parameters.rst

@@ -417,6 +417,12 @@ Domain Boundary Conditions
     * ``Reflecting``: Particles leaving the boundary are reflected from the boundary back into the domain.
       When ``boundary.reflect_all_velocities`` is false, the sign of only the normal velocity is changed, otherwise the sign of all velocities are changed.
 
+    * ``Thermal``: Particles leaving the boundary are reflected from the boundary back into the domain
+      and their velocities are thermalized. The tangential velocity components are sampled from ``gaussian`` distribution
+      and the component normal to the boundary is sampled from ``gaussian flux`` distribution.
+      The standard deviation for these distributions should be provided for each species using
+      ``boundary.<species>.u_th``. The same standard deviation is used to sample all components.
+
 * ``boundary.reflect_all_velocities`` (`bool`) optional (default `false`)
     For a reflecting boundary condition, this flags whether the sign of only the normal velocity is changed or all velocities.