PSATD: Implement First-Order Equations (#3466)

* Implement First-Order PSATD Equations

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Fix Unused Parameter Warning

* Fix RZ Build

* Fix Normalization of G to Match PML

* Add CI Test: 3D Uniform Plasma

* Cleaning

* Update 2D CI Checksums

* Update 3D CI Checksums

* Add F,G to CI Checksums of `uniform_plasma_multiJ`

* Allow User to Choose First-Order v. Second-Order

* Add WARPX_ALWAYS_ASSERT_WITH_MESSAGE

* Rename New Class `PsatdAlgorithmFirstOrder`

* Remove Inline Comment

* Update RZ CI Checksums

* Fix inline comment

* Use auxiliary variables to avoid divisions

* Use auxiliary variables to avoid divisions

* Make `nci_psatd_stability` dir and merge inputs

* Move all Galilean tests to `nci_psatd_stability`

* Fix CI

* Fix index for backward FFT of J

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

1 files changed, 9 insertions, 12 deletions

diff --git a/Source/Evolve/WarpXEvolve.cpp b/Source/Evolve/WarpXEvolve.cpp
index e8e6a025b..8abfa0e7f 100644
--- a/Source/Evolve/WarpXEvolve.cpp
+++ b/Source/Evolve/WarpXEvolve.cpp
@@ -549,14 +549,14 @@ WarpX::OneStep_multiJ (const amrex::Real cur_time)
 
     // 3) Deposit rho (in rho_new, since it will be moved during the loop)
     //    (after checking that pointer to rho_fp on MR level 0 is not null)
-    if (rho_fp[0])
+    if (rho_fp[0] && rho_in_time == RhoInTime::Linear)
     {
         // Deposit rho at relative time -dt
         // (dt[0] denotes the time step on mesh refinement level 0)
         mypc->DepositCharge(rho_fp, -dt[0]);
         // Filter, exchange boundary, and interpolate across levels
         SyncRho();
-        // Forward FFT of rho_new
+        // Forward FFT of rho
         PSATDForwardTransformRho(rho_fp, rho_cp, 0, 1);
     }
 
@@ -587,17 +587,14 @@ WarpX::OneStep_multiJ (const amrex::Real cur_time)
     // Loop over multi-J depositions
     for (int i_depose = 0; i_depose < n_loop; i_depose++)
     {
-        // Move J deposited previously, from new to old
-        if (J_in_time == JInTime::Linear)
-        {
-            PSATDMoveJNewToJOld();
-        }
+        // Move J from new to old if J is linear in time
+        if (J_in_time == JInTime::Linear) PSATDMoveJNewToJOld();
 
         const amrex::Real t_depose_current = (J_in_time == JInTime::Linear) ?
             (i_depose-n_depose+1)*sub_dt : (i_depose-n_depose+0.5_rt)*sub_dt;
 
-        // TODO Update this when rho quadratic in time is implemented
-        const amrex::Real t_depose_charge = (i_depose-n_depose+1)*sub_dt;
+        const amrex::Real t_depose_charge = (rho_in_time == RhoInTime::Linear) ?
+            (i_depose-n_depose+1)*sub_dt : (i_depose-n_depose+0.5_rt)*sub_dt;
 
         // Deposit new J at relative time t_depose_current with time step dt
         // (dt[0] denotes the time step on mesh refinement level 0)
@@ -616,14 +613,14 @@ WarpX::OneStep_multiJ (const amrex::Real cur_time)
         // (after checking that pointer to rho_fp on MR level 0 is not null)
         if (rho_fp[0])
         {
-            // Move rho deposited previously, from new to old
-            PSATDMoveRhoNewToRhoOld();
+            // Move rho from new to old if rho is linear in time
+            if (rho_in_time == RhoInTime::Linear) PSATDMoveRhoNewToRhoOld();
 
             // Deposit rho at relative time t_depose_charge
             mypc->DepositCharge(rho_fp, t_depose_charge);
             // Filter, exchange boundary, and interpolate across levels
             SyncRho();
-            // Forward FFT of rho_new
+            // Forward FFT of rho
             PSATDForwardTransformRho(rho_fp, rho_cp, 0, 1);
         }