diff --git a/Docs/source/usage/faq.rst b/Docs/source/usage/faq.rst index 3c40f6a939a..cdeedd5f1bf 100644 --- a/Docs/source/usage/faq.rst +++ b/Docs/source/usage/faq.rst @@ -27,6 +27,30 @@ We change the default in ``cmake/dependencies/AMReX.cmake``. Note that the tiny profiler adds literally no overhead to the simulation runtime, thus we enable it by default. +What design principles should I keep in mind when creating an input file? +------------------------------------------------------------------------- + +Leave a cushion between lasers, particles, and the edge of computational domain. +The laser antenna and plasma species ``zmin`` can be less than or greater than the ``geometry.prob_hi``, +but not exactly equal. + + +What do I need to know about using the boosted frame? +----------------------------------------------------- + +The input deck can be designed in the lab frame and little modification to the physical set-up is needed -- +most of the work is done internally. +Here are a few practical items to assist in designing boosted frame simulations: + +- Ions must be explicitly included +- Best practice is to separate counter-propagating objects; things moving to the right should start with :math:`z <= 0` and things stationary or moving to the left (moving to the left in the boosted frame) should start with :math:`z > 0` +- Don't forget the general design principles listed above +- The boosted frame simulation begins at boosted time :math:`t'=0` +- Numerics and algorithms need to be adjusted, as there are numerical instabilities that arise in the boosted frame. For example, setting ``particles.use_fdtd_nci_corr=1`` for an FDTD simulation or setting ``psatd.use_default_v_galilean=1`` for a PSATD simulation. Be careful as this is overly simplistic and these options will not work in all cases. Please see the :ref:`input parameters documentation ` and the :ref:`examples ` for more information + +An in-depth discussion of the boosted frame is provided in the :ref:`moving window and optimal Lorentz boosted frame ` section. + + What kinds of RZ output do you support? ---------------------------------------