improve envelope tutorial

Author: Francesco Massimo

_extra/laser_wake_envelope.py

@@ -34,12 +34,12 @@
 #########################  Simulation parameters
 
 ##### mesh resolution
-dx                  = 0.15*um                   # longitudinal mesh resolution
-dr                  = 1*um                   # transverse mesh resolution
+dx                  = 0.14*um                   # longitudinal mesh resolution
+dr                  = 0.75*um                   # transverse mesh resolution
 dt                  = 0.9*dx/c_normalized       # integration timestep
 
 ##### simulation window size
-nx                  = 352                       # number of mesh points in the longitudinal direction
+nx                  = 384                       # number of mesh points in the longitudinal direction
 nr                  = 96                        # number of mesh points in the transverse direction
 Lx                  = nx * dx                   # longitudinal size of the simulation window
 Lr                  = nr * dr                   # transverse size of the simulation window
@@ -90,8 +90,8 @@
 
 #### laser parameters
 a0                                 = 1.8
-laser_fwhm                         = 25.5*math.sqrt(2)*fs                              # laser FWHM duration in field, i.e. FWHM duration in intensity*sqrt(2)
-laser_waist                        = 20.*um                                            # laser waist, conversion from um
+laser_fwhm                         = 25*math.sqrt(2)*fs                              # laser FWHM duration in field, i.e. FWHM duration in intensity*sqrt(2)
+laser_waist                        = 16.*um                                            # laser waist, conversion from um
 center_laser                       = Lx-1.7*laser_fwhm                                 # laser position at the start of the simulation
 x_focus_laser                      = 500*um
 
@@ -125,7 +125,7 @@
 # atomic density
 plasma_plateau_density_1_ov_cm3    = 1.3e18
 n_at                               = plasma_plateau_density_1_ov_cm3*1e6/ncrit  # plasma plateau density in units of critical density defined above
-R_plasma                           = 90.*um                                     # Radius of plasma
+R_plasma                           = 65.*um                                     # Radius of plasma
 
 # Define the density function
 # this plasma density profile tries to create the density distribution

advanced_wakefield_envelope.rst

@@ -307,7 +307,7 @@ the ``"explicit_reduced_dispersion"``. Try have at least ``dt>=0.9*dx`` to use
 the B-TIS3, but check that the solver results (i.e. the envelope fields) do not
 increase exponentially due to a too high ``dt``.
 
-**Action**: Run a new simulation, changing the variable ``use_BTIS3_interpolation`` 
+**Action**: Run the same simulation again in a new folder, changing the variable ``use_BTIS3_interpolation`` 
 before the ``Main`` block to ``True``. Note how this changes the ``pusher`` 
 to ``"ponderomotive_borisBTIS3"`` and adds some fields to the ``Probes`` in the namelist. 
 Check how the electron beam shape changes::