Add parameter for default galilean velocity (#1097)

* Add parameter for default galilean velocity

* Apply suggestions from code review

Co-authored-by: Edoardo Zoni <59625522+EZoni@users.noreply.github.com>

* Fix bug in constructor of PhysicalParticleContainer

* Use new input parameter in CI test

Co-authored-by: Edoardo Zoni <59625522+EZoni@users.noreply.github.com>
Co-authored-by: Edoardo Zoni <ezoni@lbl.gov>

1 files changed, 9 insertions, 2 deletions

diff --git a/Source/WarpX.cpp b/Source/WarpX.cpp
index 498e4d02d..2163a7c79 100644
--- a/Source/WarpX.cpp
+++ b/Source/WarpX.cpp
@@ -743,11 +743,18 @@ WarpX::ReadParameters ()
         }
 
         pp.query("current_correction", current_correction);
-        pp.query("v_galilean", m_v_galilean);
         pp.query("v_comoving", m_v_comoving);
         pp.query("do_time_averaging", fft_do_time_averaging);
 
-        // Scale the velocity by the speed of light
+        // Check whether the default Galilean velocity should be used
+        bool use_default_v_galilean = false;
+        pp.query("use_default_v_galilean", use_default_v_galilean);
+        if (use_default_v_galilean) {
+            m_v_galilean[2] = -std::sqrt(1._rt - 1._rt / (gamma_boost * gamma_boost));
+        } else {
+            pp.query("v_galilean", m_v_galilean);
+        }
+        // Scale the Galilean/comoving velocity by the speed of light
         for (int i=0; i<3; i++) m_v_galilean[i] *= PhysConst::c;
         for (int i=0; i<3; i++) m_v_comoving[i] *= PhysConst::c;