Moving Frame Field Probe Functionality

Docs/source/usage/parameters.rst

@@ -2314,6 +2314,7 @@ Reduced Diagnostics
         otherwise it is set to ``1``.
         Integrated electric and magnetic field components can instead be obtained by specifying
         ``<reduced_diags_name>.integrate == true``.
+        In a *moving window* simulation, the FieldProbe can be set to follow the moving frame by specifying ``<reduced_diags_name>.do_moving_window_FP = 1`` (default 0).
 
         .. warning::
 

Examples/Physics_applications/laser_acceleration/inputs_1d

@@ -70,3 +70,15 @@ diagnostics.diags_names = diag1
 diag1.intervals = 100
 diag1.diag_type = Full
 diag1.fields_to_plot = Ex Ey Ez Bx By Bz jx jy jz rho
+
+# Reduced Diagnostics
+warpx.reduced_diags_names               = FP
+
+FP.type = FieldProbe
+FP.intervals = 10
+FP.integrate = 0
+FP.probe_geometry = Line
+FP.z_probe = -56e-6
+FP.z1_probe = 12e-6
+FP.resolution = 100
+FP.do_moving_window_FP = 1

Examples/Physics_applications/laser_acceleration/inputs_2d

@@ -87,3 +87,17 @@ diagnostics.diags_names = diag1
 diag1.intervals = 200
 diag1.diag_type = Full
 diag1.fields_to_plot = Ex Ey Ez Bx By Bz jx jy jz rho
+
+# Reduced Diagnostics
+warpx.reduced_diags_names               = FP
+
+FP.type = FieldProbe
+FP.intervals = 10
+FP.integrate = 0
+FP.probe_geometry = Line
+FP.x_probe = 0
+FP.z_probe = -56e-6
+FP.x1_probe = 0
+FP.z1_probe = 12e-6
+FP.resolution = 300
+FP.do_moving_window_FP = 1

Examples/Physics_applications/laser_acceleration/inputs_3d

@@ -77,3 +77,19 @@ diagnostics.diags_names = diag1
 diag1.intervals = 100
 diag1.diag_type = Full
 diag1.fields_to_plot = Ex Ey Ez Bx By Bz jx jy jz rho
+
+# Reduced Diagnostics
+warpx.reduced_diags_names               = FP
+
+FP.type = FieldProbe
+FP.intervals = 10
+FP.integrate = 0
+FP.probe_geometry = Line
+FP.x_probe = 0
+FP.y_probe = 0
+FP.z_probe = -56e-6
+FP.x1_probe = 0
+FP.y1_probe = 0
+FP.z1_probe = 12e-6
+FP.resolution = 300
+FP.do_moving_window_FP = 1

Source/Diagnostics/ReducedDiags/FieldProbe.H

@@ -76,6 +76,9 @@ private:
     //! counts number of particles for all MPI ranks
     long m_valid_particles {0};
 
+    //! remember the last time @see ComputeDiags was called to count the number of steps in between (for non-integrated detectors)
+    int m_last_compute_step = 0;
+
     //! determines geometry of detector point distribution
     DetectorGeometry m_probe_geometry = DetectorGeometry::Point;
 
@@ -100,6 +103,9 @@ private:
     //! Judges whether to gather raw fields or interpolated data
     bool raw_fields = false;
 
+    //! Judges whether to follow a moving window
+    bool do_moving_window_FP = false;
+
     /**
      * Built-in function in ReducedDiags to write out test data
      */

Source/Diagnostics/ReducedDiags/FieldProbe.cpp

@@ -8,6 +8,8 @@
 #include "FieldProbe.H"
 #include "FieldProbeParticleContainer.H"
 #include "Particles/Gather/FieldGather.H"
+#include "Particles/Pusher/GetAndSetPosition.H"
+#include "Particles/Pusher/UpdatePosition.H"
 
 #include "Utils/IntervalsParser.H"
 #include "Utils/TextMsg.H"
@@ -147,6 +149,7 @@ FieldProbe::FieldProbe (std::string rd_name)
     pp_rd_name.query("integrate", m_field_probe_integrate);
     pp_rd_name.query("raw_fields", raw_fields);
     pp_rd_name.query("interp_order", interp_order);
+    pp_rd_name.query("do_moving_window_FP", do_moving_window_FP);
 
     if (WarpX::gamma_boost > 1.0_rt)
     {
@@ -385,6 +388,18 @@ void FieldProbe::ComputeDiags (int step)
     {
         const amrex::Geometry& gm = warpx.Geom(lev);
         const auto prob_lo = gm.ProbLo();
+        amrex::Real const dt = WarpX::GetInstance().getdt(lev);
+        // Calculates particle movement in moving window sims
+        amrex::Real move_dist = 0.0;
+        bool const update_particles_moving_window =
+            do_moving_window_FP &&
+            step > warpx.start_moving_window_step &&
+            step <= warpx.end_moving_window_step;
+        if (update_particles_moving_window)
+        {
+            int step_diff = step - m_last_compute_step;
+            move_dist = dt*warpx.moving_window_v*step_diff;
+        }
 
         // get MultiFab data at lev
         const amrex::MultiFab &Ex = warpx.getEfield(lev, 0);
@@ -426,8 +441,30 @@ void FieldProbe::ComputeDiags (int step)
         for (MyParIter pti(m_probe, lev); pti.isValid(); ++pti)
         {
             const auto getPosition = GetParticlePosition(pti);
-            auto const np = pti.numParticles();
+            auto setPosition = SetParticlePosition(pti);
 
+            auto const np = pti.numParticles();
+            if (update_particles_moving_window)
+            {
+                const auto temp_warpx_moving_window = warpx.moving_window_dir;
+                amrex::ParallelFor( np, [=] AMREX_GPU_DEVICE (long ip)
+                {
+                    amrex::ParticleReal xp, yp, zp;
+                    getPosition(ip, xp, yp, zp);
+                    if (temp_warpx_moving_window == 0)
+                    {
+                        setPosition(ip, xp+move_dist, yp, zp);
+                    }
+                    if (temp_warpx_moving_window == 1)
+                    {
+                        setPosition(ip, xp, yp+move_dist, zp);
+                    }
+                    if (temp_warpx_moving_window == WARPX_ZINDEX)
+                    {
+                        setPosition(ip, xp, yp, zp+move_dist);
+                    }
+                });
+            }
             if( ProbeInDomain() )
             {
                 const auto cell_size = gm.CellSizeArray();
@@ -479,7 +516,6 @@ void FieldProbe::ComputeDiags (int step)
                 const int temp_interp_order = interp_order;
                 const bool temp_raw_fields = raw_fields;
                 const bool temp_field_probe_integrate = m_field_probe_integrate;
-                amrex::Real const dt = WarpX::GetInstance().getdt(lev);
 
                 // Interpolating to the probe positions for each particle
                 amrex::ParallelFor( np, [=] AMREX_GPU_DEVICE (long ip)
@@ -614,6 +650,7 @@ void FieldProbe::ComputeDiags (int step)
     }// end loop over refinement levels
     // make sure data is in m_data on the IOProcessor
     // TODO: In the future, we want to use a parallel I/O method instead (plotfiles or openPMD)
+    m_last_compute_step = step;
 } // end void FieldProbe::ComputeDiags
 
 void FieldProbe::WriteToFile (int step) const

Source/Particles/Pusher/GetAndSetPosition.H

@@ -155,7 +155,9 @@ struct SetParticlePosition
 #if defined(WARPX_DIM_RZ)
     RType* AMREX_RESTRICT m_theta;
 #endif
-    SetParticlePosition (WarpXParIter& a_pti, int a_offset = 0) noexcept
+
+    template <typename ptiType>
+    SetParticlePosition (const ptiType& a_pti, int a_offset = 0) noexcept
     {
         auto& aos = a_pti.GetArrayOfStructs();
         m_structs = aos().dataPtr() + a_offset;