Fix: 1D Field Init in z

Author: ax3l

Source/Initialization/WarpXInitData.cpp

@@ -1007,8 +1007,8 @@ WarpX::InitializeExternalFieldsOnGridUsingParser (
 #if defined(WARPX_DIM_1D_Z)
                 amrex::Real x = 0._rt;
                 amrex::Real y = 0._rt;
-                amrex::Real fac_z = (1._rt - z_nodal_flag[1]) * dx_lev[1] * 0.5_rt;
-                amrex::Real z = j*dx_lev[1] + real_box.lo(1) + fac_z;
+                amrex::Real fac_z = (1._rt - z_nodal_flag[0]) * dx_lev[0] * 0.5_rt;
+                amrex::Real z = j*dx_lev[0] + real_box.lo(0) + fac_z;
 #elif defined(WARPX_DIM_XZ) || defined(WARPX_DIM_RZ)
                 amrex::Real fac_x = (1._rt - z_nodal_flag[0]) * dx_lev[0] * 0.5_rt;
                 amrex::Real x = i*dx_lev[0] + real_box.lo(0) + fac_x;