def add_coil(pos, N, normal=[0,0,1], width=5.3e-3, r_o=30.25e-3 - 1e-3, r_i=5e-3, current=1):
# pos is coil midpoint
A = width * (r_o - r_i)
A_loop = A/N
d_loop = np.sqrt(A_loop)
N_d = int(round(width/d_loop))
N_r = int(round((r_o-r_i)/d_loop))
N_prod = N_d * N_r
print("building coil with %d x %d = %d loops, error = %d ( %.2g percent)" % (N_d, N_r, N_prod, N_prod - N, 100 * np.abs((N_prod - N) / N)))
radiuses = np.linspace(r_i, r_o, N_r)
mid_points = pos + np.outer(np.linspace(-width/2, width/2, N_d), normal)
for radius in (radiuses):
for mid_point in (mid_points):
field.addLoop(loopfield.Loop(mid_point, normal, radius, current))
# Maxwell coil plot example
#
import math
import loopfield as lf
import loopfield.plot as lfp
# field object
field = lf.Field(length_units=lf.cm, current_units=lf.A, field_units=lf.uT)
# Maxwell coil model with single current loops
R = 10
# center winding
c1 = lf.Loop([0, 0, 0], [1, 0, 0], R, 64)
# outer windings
c2 = lf.Loop([-R * math.sqrt(3. / 7.), 0, 0], [1, 0, 0],
R * math.sqrt(4. / 7.), 49)
c3 = lf.Loop([+R * math.sqrt(3. / 7.), 0, 0], [1, 0, 0],
R * math.sqrt(4. / 7.), 49)
# add windings to field
field.addLoop(c1)
field.addLoop(c2)
field.addLoop(c3)
# evaluate field at center of coil
Bc = field.evaluate([0., 0., 0.])
print('Bc = ', Bc)
#
# Helmholtz coil plot example
#
import math
import loopfield as lf
import loopfield.plot as lfp
# field object
field = lf.Field(length_units=lf.cm, current_units=lf.A, field_units=lf.uT)
# Helmholtz coil model with single current loops
R = 10.
# 2 windings
c1 = lf.Loop([-R / 2., 0, 0], [1, 0, 0], R, 1)
c2 = lf.Loop([+R / 2., 0, 0], [1, 0, 0], R, 1)
# add windings to field
field.addLoop(c1)
field.addLoop(c2)
# evaluate field at center of coil
Bc = field.evaluate([0., 0., 0.])
print('Bc = ', Bc)
print('Calculating plot...')
# function returns ratio of x-component to that at coil center
def x_ratio(B):
#!/usr/bin/env python3
import loopfield as lf
# create empty field with specified units
field = lf.Field(length_units=lf.cm, current_units=lf.A, field_units=lf.uT)
# single-turn 10 cm x-oriented coil at origin
position = [0., 0., 0.]
normal = [1., 0., 0.]
radius = 10.
current = 1.
c = lf.Loop(position, normal, radius, current)
# add loop to field
field.addLoop(c)
# evaluate vector field at origin
B = field.evaluate([0., 0., 0.])
print('B = ', B)
# evaluate vector field 100 cm along axis
B = field.evaluate([100., 0., 0.])
print('B = ', B)
# evaluate vector field on loop (infinite result)
B = field.evaluate([0., radius, 0.])
print('B = ', B)