Merge pull request #121 from ECP-WarpX/parab_profile

add parameter z_start for parabolic chanel profile

1 files changed, 12 insertions, 11 deletions

diff --git a/Source/Initialization/PlasmaProfiles.cpp b/Source/Initialization/PlasmaProfiles.cpp
index e3382db06..d9d207f7e 100644
--- a/Source/Initialization/PlasmaProfiles.cpp
+++ b/Source/Initialization/PlasmaProfiles.cpp
@@ -17,21 +17,22 @@ Real PredefinedDensityProfile::getDensity(Real x, Real y, Real z) const {
 /// plateau between linear upramp and downramp, and parab transverse profile
 ///
 Real PredefinedDensityProfile::ParabolicChannel(Real x, Real y, Real z) const {
-    //  params = [ramp_up   plateau   ramp_down   rc       n0]
-    Real ramp_up   = params[0];
-    Real plateau   = params[1];
-    Real ramp_down = params[2];
-    Real rc        = params[3];
-    Real n0        = params[4];
+    //  params = [z_start   ramp_up   plateau   ramp_down   rc       n0]
+    Real z_start   = params[0];
+    Real ramp_up   = params[1];
+    Real plateau   = params[2];
+    Real ramp_down = params[3];
+    Real rc        = params[4];
+    Real n0        = params[5];
     Real n;
     Real kp = PhysConst::q_e/PhysConst::c*sqrt( n0/(PhysConst::m_e*PhysConst::ep0) );
 
-    if        (z>=0               and z<ramp_up                  ) {
-        n = z/ramp_up;
-    } else if (z>=ramp_up         and z<ramp_up+plateau          ) {
+    if        ((z-z_start)>=0               and (z-z_start)<ramp_up                  ) {
+        n = (z-z_start)/ramp_up;
+    } else if ((z-z_start)>=ramp_up         and (z-z_start)<ramp_up+plateau          ) {
         n = 1;
-    } else if (z>=ramp_up+plateau and z<ramp_up+plateau+ramp_down) {
-        n = 1-(z-ramp_up-plateau)/ramp_down;
+    } else if ((z-z_start)>=ramp_up+plateau and (z-z_start)<ramp_up+plateau+ramp_down) {
+        n = 1-((z-z_start)-ramp_up-plateau)/ramp_down;
     } else {
         n = 0;
     }