General moving-window transformations in boosted-frame simulations (E…

…CP-WarpX#5226) * General moving-window transformations in boosted-frame simulations * Default speed of moving window to speed of boosted frame * Extend simulation volume enough so that particles don't exit * Include moving window speed in diag_lo and diag_hi transformations * Modify bounds so as to produce the same results as in previous versions --------- Co-authored-by: Remi Lehe <[email protected]>
JustinRayAngus · Sep 28, 2024 · eef12e9 · eef12e9
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Showing 8 changed files with 94 additions and 76 deletions.
diff --git a/Examples/Tests/accelerator_lattice/inputs_test_3d_hard_edged_quadrupoles_boosted b/Examples/Tests/accelerator_lattice/inputs_test_3d_hard_edged_quadrupoles_boosted
@@ -2,8 +2,8 @@ max_step = 50
 amr.n_cell = 16 16 8
 amr.max_level = 0
 geometry.dims = 3
-geometry.prob_lo     = -0.2 -0.2 -0.1
-geometry.prob_hi     = +0.2 +0.2 +0.1
+geometry.prob_lo     = -0.2 -0.2 -0.1866
+geometry.prob_hi     = +0.2 +0.2 +0.1866
 
 # Boundary condition
 boundary.field_lo = pec pec pec

diff --git a/Examples/Tests/plasma_lens/inputs_test_3d_plasma_lens_boosted b/Examples/Tests/plasma_lens/inputs_test_3d_plasma_lens_boosted
@@ -8,8 +8,8 @@ amr.max_level = 0
 
 # Geometry
 geometry.dims = 3
-geometry.prob_lo     = -1.0  -1.0  -1.0   # physical domain
-geometry.prob_hi     =  1.0   1.0   2.0
+geometry.prob_lo     = -1.0  -1.0  -1.866   # physical domain
+geometry.prob_hi     =  1.0   1.0   3.732
 
 boundary.field_lo = pec pec pec
 boundary.field_hi = pec pec pec

diff --git a/Regression/Checksum/benchmarks_json/test_3d_hard_edged_quadrupoles_boosted.json b/Regression/Checksum/benchmarks_json/test_3d_hard_edged_quadrupoles_boosted.json
@@ -1,22 +1,22 @@
 {
+  "lev=0": {
+    "Bx": 3.254604354043409e-14,
+    "By": 3.2768679907552955e-14,
+    "Bz": 1.0615351421410278e-16,
+    "Ex": 2.3084916770539354e-05,
+    "Ey": 2.2657235922655432e-05,
+    "Ez": 1.9978004351148e-05,
+    "jx": 1.781971994166362e-10,
+    "jy": 4.2163624424546344e-20,
+    "jz": 1.0378980680353126e-07
+  },
   "electron": {
-    "particle_momentum_x": 5.955475926588059e-26,
-    "particle_momentum_y": 1.4612764777454504e-35,
-    "particle_momentum_z": 3.4687284535374423e-23,
-    "particle_position_x": 0.049960237123814574,
-    "particle_position_y": 8.397636119991403e-15,
-    "particle_position_z": 0.10931687737912647,
+    "particle_momentum_x": 5.955475927655105e-26,
+    "particle_momentum_y": 1.4613271542201658e-35,
+    "particle_momentum_z": 3.468728453537439e-23,
+    "particle_position_x": 0.04996023704063194,
+    "particle_position_y": 8.398113230295983e-15,
+    "particle_position_z": 0.10931682580470406,
     "particle_weight": 1.0
-  },
-  "lev=0": {
-    "Bx": 3.254531465641299e-14,
-    "By": 3.2768092409497234e-14,
-    "Bz": 1.0615286316115558e-16,
-    "Ex": 2.30845657253269e-05,
-    "Ey": 2.2656898931877975e-05,
-    "Ez": 1.997747654112569e-05,
-    "jx": 1.7819477343635878e-10,
-    "jy": 4.2163030523377745e-20,
-    "jz": 1.0378839382497739e-07
   }
 }
diff --git a/Regression/Checksum/benchmarks_json/test_3d_plasma_lens_boosted.json b/Regression/Checksum/benchmarks_json/test_3d_plasma_lens_boosted.json
@@ -1,21 +1,21 @@
 {
   "lev=0": {
-    "Bx": 1.3073041371012706e-14,
-    "By": 1.3033038210840872e-14,
-    "Bz": 5.595105968291083e-17,
-    "Ex": 2.801134785671445e-06,
-    "Ey": 2.8088613469887243e-06,
-    "Ez": 3.343430731047825e-06,
-    "jx": 2.5155716299904363e-11,
-    "jy": 2.013718424043256e-11,
-    "jz": 6.00631499206418e-09
+    "Bx": 1.307357220398482e-14,
+    "By": 1.3033571630685163e-14,
+    "Bz": 5.594998319468307e-17,
+    "Ex": 2.8010832905044288e-06,
+    "Ey": 2.8088096742407935e-06,
+    "Ez": 3.3433681277560495e-06,
+    "jx": 2.5151718871714067e-11,
+    "jy": 2.013398608921663e-11,
+    "jz": 6.0063967622563335e-09
   },
   "electrons": {
-    "particle_momentum_x": 7.437088723328491e-24,
-    "particle_momentum_y": 5.9495056615288754e-24,
-    "particle_momentum_z": 5.117548636687908e-22,
-    "particle_position_x": 0.036489969262013186,
-    "particle_position_y": 0.029201200231260247,
-    "particle_position_z": 6.9681085285694095
+    "particle_momentum_x": 7.43708887164806e-24,
+    "particle_momentum_y": 5.949505779760011e-24,
+    "particle_momentum_z": 5.117548636790359e-22,
+    "particle_position_x": 0.03648994812700447,
+    "particle_position_y": 0.029201183320618985,
+    "particle_position_z": 6.968107021318396
   }
-}
+}
diff --git a/Source/Diagnostics/Diagnostics.cpp b/Source/Diagnostics/Diagnostics.cpp
@@ -229,8 +229,9 @@ Diagnostics::BaseReadParameters ()
        if (WarpX::boost_direction[ dim_map[WarpX::moving_window_dir] ] == 1) {
            // Convert user-defined lo and hi for diagnostics to account for boosted-frame
            // simulations with moving window
-           const amrex::Real convert_factor = 1._rt/(WarpX::gamma_boost * (1._rt - WarpX::beta_boost) );
-           // Assuming that the window travels with speed c
+           const amrex::Real beta_window = WarpX::moving_window_v / PhysConst::c;
+           const amrex::Real convert_factor = 1._rt/(
+               WarpX::gamma_boost * (1._rt - WarpX::beta_boost * beta_window) );
            m_lo[WarpX::moving_window_dir] *= convert_factor;
            m_hi[WarpX::moving_window_dir] *= convert_factor;
        }

diff --git a/Source/Utils/WarpXUtil.H b/Source/Utils/WarpXUtil.H
@@ -33,6 +33,10 @@ void ParseGeometryInput();
 void ReadBoostedFrameParameters(amrex::Real& gamma_boost, amrex::Real& beta_boost,
                                 amrex::Vector<int>& boost_direction);
 
+void ReadMovingWindowParameters(
+    int& do_moving_window, int& start_moving_window_step, int& end_moving_window_step,
+    int& moving_window_dir, amrex::Real& moving_window_v);
+
 void ConvertLabParamsToBoost();
 
 /**

diff --git a/Source/Utils/WarpXUtil.cpp b/Source/Utils/WarpXUtil.cpp
@@ -140,6 +140,43 @@ void ReadBoostedFrameParameters(Real& gamma_boost, Real& beta_boost,
     }
 }
 
+void ReadMovingWindowParameters(
+    int& do_moving_window, int& start_moving_window_step, int& end_moving_window_step,
+    int& moving_window_dir, amrex::Real& moving_window_v)
+{
+    const ParmParse pp_warpx("warpx");
+    pp_warpx.query("do_moving_window", do_moving_window);
+    if (do_moving_window) {
+        utils::parser::queryWithParser(
+            pp_warpx, "start_moving_window_step", start_moving_window_step);
+        utils::parser::queryWithParser(
+            pp_warpx, "end_moving_window_step", end_moving_window_step);
+        std::string s;
+        pp_warpx.get("moving_window_dir", s);
+
+        if (s == "z" || s == "Z") {
+            moving_window_dir = WARPX_ZINDEX;
+        }
+#if defined(WARPX_DIM_3D)
+        else if (s == "y" || s == "Y") {
+            moving_window_dir = 1;
+        }
+#endif
+#if defined(WARPX_DIM_XZ) || defined(WARPX_DIM_3D)
+        else if (s == "x" || s == "X") {
+            moving_window_dir = 0;
+        }
+#endif
+        else {
+            WARPX_ABORT_WITH_MESSAGE("Unknown moving_window_dir: "+s);
+        }
+
+        utils::parser::getWithParser(
+            pp_warpx, "moving_window_v", moving_window_v);
+        moving_window_v *= PhysConst::c;
+    }
+}
+
 void ConvertLabParamsToBoost()
 {
     Real gamma_boost = 1., beta_boost = 0.;
@@ -196,8 +233,11 @@ void ConvertLabParamsToBoost()
     {
         if (boost_direction[dim_map[idim]]) {
             amrex::Real convert_factor;
-            // Assume that the window travels with speed +c
-            convert_factor = 1._rt/( gamma_boost * ( 1 - beta_boost ) );
+            amrex::Real beta_window = beta_boost;
+            if (WarpX::do_moving_window && idim == WarpX::moving_window_dir) {
+                beta_window = WarpX::moving_window_v / PhysConst::c;
+            }
+            convert_factor = 1._rt/( gamma_boost * ( 1 - beta_boost * beta_window ) );
             prob_lo[idim] *= convert_factor;
             prob_hi[idim] *= convert_factor;
             if (max_level > 0){

diff --git a/Source/WarpX.cpp b/Source/WarpX.cpp
@@ -200,6 +200,10 @@ void WarpX::MakeWarpX ()
 {
     ParseGeometryInput();
 
+    ReadMovingWindowParameters(
+        do_moving_window, start_moving_window_step, end_moving_window_step,
+        moving_window_dir, moving_window_v);
+
     ConvertLabParamsToBoost();
     ReadBCParams();
 
@@ -623,42 +627,11 @@ WarpX::ReadParameters ()
         pp_warpx.query("compute_max_step_from_btd",
             compute_max_step_from_btd);
 
-        pp_warpx.query("do_moving_window", do_moving_window);
-        if (do_moving_window)
-        {
-            utils::parser::queryWithParser(
-                pp_warpx, "start_moving_window_step", start_moving_window_step);
-            utils::parser::queryWithParser(
-                pp_warpx, "end_moving_window_step", end_moving_window_step);
-            std::string s;
-            pp_warpx.get("moving_window_dir", s);
-
-            if (s == "z" || s == "Z") {
-                moving_window_dir = WARPX_ZINDEX;
-            }
-#if defined(WARPX_DIM_3D)
-            else if (s == "y" || s == "Y") {
-                moving_window_dir = 1;
-            }
-#endif
-#if defined(WARPX_DIM_XZ) || defined(WARPX_DIM_3D)
-            else if (s == "x" || s == "X") {
-                moving_window_dir = 0;
-            }
-#endif
-
-            else {
-                WARPX_ABORT_WITH_MESSAGE("Unknown moving_window_dir: "+s);
-            }
-
-            WARPX_ALWAYS_ASSERT_WITH_MESSAGE(Geom(0).isPeriodic(moving_window_dir) == 0,
-                       "The problem must be non-periodic in the moving window direction");
-
+        if (do_moving_window) {
+            WARPX_ALWAYS_ASSERT_WITH_MESSAGE(
+                Geom(0).isPeriodic(moving_window_dir) == 0,
+                "The problem must be non-periodic in the moving window direction");
             moving_window_x = geom[0].ProbLo(moving_window_dir);
-
-            utils::parser::getWithParser(
-                pp_warpx, "moving_window_v", moving_window_v);
-            moving_window_v *= PhysConst::c;
         }
 
         m_p_ext_field_params = std::make_unique<ExternalFieldParams>(pp_warpx);