If not yet available some libraries and their python bindings have to be installed :

gmsh (best installed globally through package management system)
python3 -m pip install pygmsh --user
VTK (best installed globally through package management system)
python3 -m pip install vtk --user



In [1]:

    
import numpy as np
from scipy import constants
import scipy.integrate
import scipy.special as func
from MeshedFields import *

Create a meshed screen

we use a rather poor resolution to allow a quick test - not recommended for real application



In [6]:

    
mesh = MeshedField.CircularMesh(R=1.0, ratio=1.0, lcar=0.10)
pts = [np.array([p[0],p[1],5.0]) for p in mesh.points]
screen = MeshedField(pts, mesh.triangles)

print("%d points" % len(screen.points))
print("%d triangles" % len(screen.triangles))
area = screen.MeshArea()
normals = screen.MeshNormals()
average = np.sum(normals, axis=0)/screen.Np
print("total mesh area = %7.3f cm²" % (1.0e4*np.sum(area)))
print("screen normal = %s" % average)
print("bounding box :", screen.BoundingBox())









    



464 points
858 triangles
total mesh area = 31365.485 cm²
screen normal = [ 0.  0. -1.]
bounding box : ((-1.0, 1.0), (-1.0, 1.0), (5.0, 5.0))

define the timing

The beam is assumed to start at the origin at t=0.



In [7]:

    
# time step
screen.dt = 2.0e-13
# all points use the same timing grid
screen.Nt = 400

screen.t0 = np.array([np.linalg.norm(p)/constants.c -200*screen.dt for p in screen.pos])

print("expected arrival time : ", 5.0/constants.c)
print(np.min(screen.t0))
print(np.max(screen.t0)+screen.Nt*screen.dt)
print(len(screen.t0))









    



expected arrival time :  1.6678204759907603e-08
1.66389561321e-08
1.70370981721e-08
858

Write the file

It is assumed that the script was started from the scripts directory. The file should be created in the tests folder.
The file is included with the source code, so, the test case can be run without working this script.



In [17]:

    
filename="../tests/ForwardDiffractionRadiation.h5"
screen.WriteMeshedField(filename)









    



not writing ElMagField dataset

Check the file after running the test



In [2]:

    
filename="../tests/ForwardDiffractionRadiation.h5"
computed = MeshedField.ReadMeshedField(filename)

print("%d points" % len(computed.points))
print("%d triangles" % len(computed.triangles))
area = computed.MeshArea()
normals = computed.MeshNormals()
average = np.sum(normals, axis=0)/computed.Np
print("total mesh area = %7.3f cm²" % (1.0e4*np.sum(area)))
print("screen normal = %s" % average)









    



corner points :  (464, 3)
triangles :  (858, 3)
Nt = 400   dt = 2e-13 
t0 :  (858,)
field :  (858, 400, 6)
464 points
858 triangles
total mesh area = 31365.485 cm²
screen normal = [ 0.  0. -1.]



In [3]:

    
area = computed.MeshArea()
S = [np.linalg.norm(computed.EnergyFlowVector(i)) for i in range(computed.Np)]
peak_index = np.argmax(S)
Pz = [computed.NormalEnergyFlow(i) for i in range(computed.Np)]

print("peak energy density = %.6f J/m²  index=%d" % (S[peak_index],peak_index))
print("total pulse energy = %.3f µJ" % (1e6*np.dot(area,Pz)))









    



peak energy density = 0.000000 J/m²  index=680
total pulse energy = 0.250 µJ



In [4]:

    
computed.ShowMeshedField(scalars=Pz,scalarTitle="Pz",highlight=[peak_index],showGrid=True)
computed.ShowFieldTrace(peak_index)



In [5]:

    
def pick(id):
    if id>0 and id<computed.Np:
        print("cell No. %d pos=%s" % (id,computed.pos[id]))
        print("pointing vector S=%s" % computed.EnergyFlowVector(id))
        computed.ShowFieldTrace(id)

computed.ShowMeshedField(scalars=Pz,scalarTitle="Pz",pickAction=pick,showGrid=False)









    



cell No. 274 pos=[ 0.22410517 -0.0268924   5.        ]
pointing vector S=[ -1.00364363e-08   1.20216367e-09   2.53882859e-07]






    












    



cell No. 560 pos=[ 0.73100309 -0.01287158  5.        ]
pointing vector S=[ -3.63085235e-10   6.04326056e-12   4.77171769e-08]






    












    



cell No. 793 pos=[ 0.94579814 -0.09816486  5.        ]
pointing vector S=[ -1.27128152e-10   1.30635290e-11   2.52307211e-08]



In [ ]: