add dohi example file

examples/dohi-mirror.py

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+import time
+
+ import numpy as np
+ import matplotlib.pyplot as plt
+
+ import traceon.geometry as G
+ import traceon.excitation as E
+ import traceon.tracing as T
+ import traceon.solver as S
+ import traceon.plotting as P
+ from traceon.interpolation import FieldRadialAxial
+
+
+
+ try:
+     from traceon_pro.interpolation import Field3DAxial
+ except ImportError:
+
+
+     Field3DAxial = None
+
+ PLOT_GEOM = False
+ MSF = 30
+
+ #voltages
+ TUNING_VOLTAGE = 710.0126605741955
+ MIRROR_VOLTAGE = -1250
+
+ #displacements x y z plane of seperate components
+ ground_elec_displacement = (0.,0.,0.)
+ tuning_elec_displacement = (0.,0.,0.)
+ mirror_displacement = (0.0,0.,0.)
+
+
+ rmax = 1.0
+ margin = 0.3
+ extent = rmax-0.1
+
+ t = 0.15 # thickness
+ r = 0.075 # radius
+ st = 0.5  # spacer thickness
+
+
+ #create line geometries
+ mirror = G.Path.aperture(0.15, r, extent, z=t/2)
+ mirror.name = 'mirror'
+
+ mirror_line = G.Path.line([0., 0., 0.], [r, 0., 0.])
+ mirror_line.name = 'mirror'
+
+ lens = G.Path.aperture(0.15, r, extent, z=t + st + t/2)
+ lens.name = 'lens'
+
+ ground = G.Path.aperture(0.15, r, extent, z=t+st+t+st+t/2)
+ ground.name = 'ground'
+
+ #revolve around z axis and displace
+ mirror = mirror.revolve_z()
+ mirror_line = mirror_line.revolve_z()
+ lens = lens.revolve_z()
+ ground = ground.revolve_z()
+
+ #displace electrodes
+ ground = ground.move(*ground_elec_displacement)
+ lens = lens.move(*tuning_elec_displacement)
+ mirror = mirror.move(*mirror_displacement)
+ mirror_line = mirror_line.move(*mirror_displacement)
+
+ #create geometry
+ geom = mirror+mirror_line+lens+ground
+
+ #make mesh
+ mesh =  geom.mesh(mesh_size_factor=MSF)
+
+ if PLOT_GEOM:
+     P.plot_mesh(mesh, ground='green', mirror='red', lens='blue', show_normals=True)
+
+ excitation = E.Excitation(mesh, E.Symmetry.THREE_D)
+
+ # Apply the correct voltages. Set the ground electrode to zero.
+ excitation.add_voltage(ground=0., lens=TUNING_VOLTAGE, mirror=MIRROR_VOLTAGE)
+
+ # Use the Boundary Element Method (BEM) to calculate the surface charges,
+ # the surface charges gives rise to a electrostatic field.
+ field = S.solve_direct(excitation)
+
+ tracer = field.get_tracer( [(-r/2, r/2), (-r/2, r/2), (-7, 15.1)] )
+
+ angle = 0.5e-8
+ z0 = 15
+
+ # Initial velocity vector points downwards, with a 
+ # initial speed corresponding to 1000eV.
+ start_pos = np.array([0.0, 0.0, z0])
+ start_vel = T.velocity_vec_xz_plane(1000, angle)
+
+ print('Starting trace...')
+ st = time.time()
+ _, pos_derivs = tracer(start_pos, start_vel)
+ print(f'Trace took {(time.time()-st)*1000:.1f} ms')
+ intersection = T.xy_plane_intersection(pos_derivs, z0)
+
+ print("(x,y,z)-displacements: \n")
+ print(f"ground: {ground_elec_displacement}")
+ print(f"lens: {tuning_elec_displacement}")
+ print(f"mirror: {mirror_displacement} \n")
+
+ print(f"Relative error: {np.abs(intersection[0])}")