diff options
Diffstat (limited to 'Source')
| -rw-r--r-- | Source/Evolve/WarpXEvolveEM.cpp | 48 | ||||
| -rw-r--r-- | Source/WarpX.H | 4 | ||||
| -rw-r--r-- | Source/WarpX.cpp | 8 |
3 files changed, 60 insertions, 0 deletions
diff --git a/Source/Evolve/WarpXEvolveEM.cpp b/Source/Evolve/WarpXEvolveEM.cpp index e98561be1..dab58f95b 100644 --- a/Source/Evolve/WarpXEvolveEM.cpp +++ b/Source/Evolve/WarpXEvolveEM.cpp @@ -25,6 +25,10 @@ WarpX::EvolveEM (int numsteps) static int last_check_file_step = 0; static int last_insitu_step = 0; + if (do_compute_max_step_from_zmax){ + computeMaxStepBoostAccelerator(geom[0]); + } + int numsteps_max; if (numsteps < 0) { // Note that the default argument is numsteps = -1 numsteps_max = max_step; @@ -503,6 +507,50 @@ WarpX::ComputeDt () } } +/* \brief computes max_step for wakefield simulation in boosted frame. + * \param geom: Geometry object that contains simulation domain. + * + * max_step is set so that the simulation stop when the lower corner of the + * simulation box passes input parameter zmax_plasma_to_compute_max_step. + */ +void +WarpX::computeMaxStepBoostAccelerator(amrex::Geometry geom){ + // Sanity checks: can use zmax_plasma_to_compute_max_step only if + // the moving window and the boost are all in z direction. + AMREX_ALWAYS_ASSERT_WITH_MESSAGE( + WarpX::moving_window_dir == AMREX_SPACEDIM-1, + "Can use zmax_plasma_to_compute_max_step only if " + + "moving window along z. TODO: all directions."); + AMREX_ALWAYS_ASSERT_WITH_MESSAGE( + maxLevel() == 0, + "Can use zmax_plasma_to_compute_max_step only if " + + "max level = 0."); + AMREX_ALWAYS_ASSERT_WITH_MESSAGE( + (WarpX::boost_direction[0]-0)*(WarpX::boost_direction[0]-0) + + (WarpX::boost_direction[1]-0)*(WarpX::boost_direction[1]-0) + + (WarpX::boost_direction[2]-1)*(WarpX::boost_direction[2]-1) < 1.e-12, + "Can use zmax_plasma_to_compute_max_step only if " + + "warpx.boost_direction = z. TODO: all directions."); + + // Lower end of the simulation domain. All quantities are given in boosted + // frame except zmax_plasma_to_compute_max_step. + const Real zmin_domain_boost = geom.ProbLo(AMREX_SPACEDIM-1); + // End of the plasma: Transform input argument + // zmax_plasma_to_compute_max_step to boosted frame. + const Real len_plasma_boost = zmax_plasma_to_compute_max_step/gamma_boost; + // Plasma velocity + const Real v_plasma_boost = -beta_boost * PhysConst::c; + // Get time at which the lower end of the simulation domain passes the + // upper end of the plasma (in the z direction). + const Real interaction_time_boost = (len_plasma_boost-zmin_domain_boost)/ + (moving_window_v-v_plasma_boost); + // Divide by dt, and update value of max_step. + const int computed_max_step = interaction_time_boost/dt[0]; + max_step = computed_max_step; + Print()<<"max_step computed in computeMaxStepBoostAccelerator: " + <<computed_max_step<<std::endl; +} + /* \brief Apply perfect mirror condition inside the box (not at a boundary). * In practice, set all fields to 0 on a section of the simulation domain * (as for a perfect conductor with a given thickness). diff --git a/Source/WarpX.H b/Source/WarpX.H index a7a356afc..71fc54af2 100644 --- a/Source/WarpX.H +++ b/Source/WarpX.H @@ -108,6 +108,8 @@ public: static amrex::Real gamma_boost; static amrex::Real beta_boost; static amrex::Vector<int> boost_direction; + static amrex::Real zmax_plasma_to_compute_max_step; + static int do_compute_max_step_from_zmax; static bool do_dynamic_scheduling; static bool refine_plasma; @@ -152,6 +154,8 @@ public: void applyMirrors(amrex::Real time); void ComputeDt (); + // Compute max_step automatically for simulations in a boosted frame. + void computeMaxStepBoostAccelerator(amrex::Geometry geom); int MoveWindow (bool move_j); void UpdatePlasmaInjectionPosition (amrex::Real dt); diff --git a/Source/WarpX.cpp b/Source/WarpX.cpp index 661399ea3..eb84af2c7 100644 --- a/Source/WarpX.cpp +++ b/Source/WarpX.cpp @@ -32,6 +32,8 @@ int WarpX::moving_window_dir = -1; Real WarpX::gamma_boost = 1.; Real WarpX::beta_boost = 0.; Vector<int> WarpX::boost_direction = {0,0,0}; +int WarpX::do_compute_max_step_from_zmax = 0; +Real WarpX::zmax_plasma_to_compute_max_step = 0.; long WarpX::current_deposition_algo = 3; long WarpX::charge_deposition_algo = 0; @@ -272,6 +274,12 @@ WarpX::ReadParameters () ReadBoostedFrameParameters(gamma_boost, beta_boost, boost_direction); + // pp.query returns 1 if argument zmax_plasma_to_compute_max_step is + // specified by the user, 0 otherwise. + do_compute_max_step_from_zmax = + pp.query("zmax_plasma_to_compute_max_step", + zmax_plasma_to_compute_max_step); + pp.queryarr("B_external", B_external); pp.query("do_moving_window", do_moving_window); |