File:VFPt dipoles magnetic.svg
From KYNNpedia
Size of this PNG preview of this SVG file: 600 × 600 pixels. Other resolutions: 240 × 240 pixels | 480 × 480 pixels | 768 × 768 pixels | 1,024 × 1,024 pixels | 2,048 × 2,048 pixels | 840 × 840 pixels.
Original file (SVG file, nominally 840 × 840 pixels, file size: 103 KB)
Summary
| Description |
English: Computed drawings of four different types of magnetic dipoles. Upper left: An ideal point-like dipole. The field shape is scale invariant and approximates the field of any magnetized volume with nonzero dipole moment at large distance. |
| Date | |
| Source | Own work |
| Author | Geek3 |
| Other versions | VFPt dipoles electric.svg |
| SVG development |  This plot was created with VectorFieldPlot.  This file is translated using SVG switch elements: all translations are stored in the same file. |
| Source code | Python code# paste this code at the end of VectorFieldPlot 2.5
R = 0.6
h = 0.6
rsym = 21
doc = FieldplotDocument('VFPt_dipoles_magnetic1', commons=True,
width=360, height=360)
field = Field([ ['dipole', {'x':0, 'y':0, 'px':0., 'py':1.}] ])
def f_arrows(xy):
return xy[1] * (sc.hypot(xy[0], xy[1]) / 1.4 - 1)
def f_cond(xy):
return hypot(*xy) > 1e-4 and (fabs(xy[1]) < 1e-3 or fabs(xy[1]) > .3)
nlines = 19
startpoints = Startpath(field, lambda t: 0.25*sc.array([sin(t), cos(t)]),
t0=-pi/2, t1=pi/2).npoints(nlines)
for p0 in startpoints:
line = FieldLine(field, p0, directions='both')
doc.draw_line(line, maxdist=1, arrows_style={'at_potentials':[0.],
'potential':f_arrows, 'condition_func':f_cond, 'scale':1.2})
# draw dipole symbol
rg_grad = etree.SubElement(doc._get_defs(), 'linearGradient')
rg_grad.set('id', 'grad_rg')
for attr, val in [ ['x1', '0'], ['x2', '0'], ['y1', '0'], ['y2', '1'] ]:
rg_grad.set(attr, val)
for col, of in [ ['#00cc00', '0'], ['#887744', '0.5'], ['#ff0000', '1'] ]:
stop = etree.SubElement(rg_grad, 'stop')
stop.set('stop-color', col)
stop.set('offset', of)
stop.set('stop-opacity', '1')
symb = doc.draw_object('g', {'id':'dipole_symbol',
'transform':'scale({0},{0})'.format(1./doc.unit)})
doc.draw_object('circle', {'cx':'0', 'cy':'0', 'r':rsym,
'fill':'url(#grad_rg)', 'stroke':'none'}, group=symb)
doc._check_whitespot()
doc.draw_object('circle', {'cx':'0', 'cy':'0', 'r':rsym,
'fill':'url(#white_spot)', 'stroke':'#000000', 'stroke-width':'3'},
group=symb)
doc.draw_object('path', {'fill':'#000000', 'stroke':'none',
'd':'M 3,-12 V 0 H 12 L 0,15 L -12,0 H -3 V -12 H 3 Z'}, group=symb)
doc.write()
doc = FieldplotDocument('VFPt_dipoles_magnetic2', commons=True,
width=360, height=360)
field = Field([ ['monopole', {'x':0, 'y':h, 'Q':1}],
['monopole', {'x':0, 'y':-h, 'Q':-1}] ])
def f_arrows(xy):
return xy[1] * (sc.hypot(xy[0], xy[1]) / 1.4 - 1)
def f_cond(xy):
return fabs(xy[0]) < 1.4
nlines = 18
stp = Startpath(field, lambda t: R*sc.array([.2*sin(t), 1+.2*cos(t)]),
t0=-pi, t1=pi)
startpoints = [stp.startpos(s) for s in sc.arange(nlines)/float(nlines)]
startpoints.append(startpoints[nlines//2].dot([ [1,0],[0,-1] ]))
for p0 in startpoints:
line = FieldLine(field, p0, directions='both', maxr=100)
doc.draw_line(line, maxdist=1, arrows_style={'at_potentials':[0.],
'potential':f_arrows, 'condition_func':f_cond, 'scale':1.2})
# draw pole symbols
symb_N = doc.draw_object('g', {'id':'north_symbol',
'transform':'translate(0,{0}) scale({1},{1})'.format(h, 1./doc.unit)})
symb_S = doc.draw_object('g', {'id':'south_symbol',
'transform':'translate(0,{0}) scale({1},{1})'.format(-h, 1./doc.unit)})
for i, g in enumerate([symb_N, symb_S]):
doc.draw_object('circle', {'cx':'0', 'cy':'0', 'r':rsym, 'stroke':'none',
'fill':['#ff0000', '#00cc00'][i]}, group=g)
doc._check_whitespot()
doc.draw_object('circle', {'cx':'0', 'cy':'0', 'r':rsym,
'fill':'url(#white_spot)', 'stroke':'#000000', 'stroke-width':'3'}, group=g)
text = etree.SubElement(g, 'text')
for attr, val in [ ['text-anchor', 'middle'], ['x', 0], ['y', 11],
['fill', '#000000'], ['stroke', 'none'], ['font-size', '32px'],
['font-family', 'Bitstream Vera Sans'],
['transform', 'scale(1, -1)'] ]:
text.set(attr, str(val))
text.text = ['N', 'S'][i]
doc.write()
doc = FieldplotDocument('VFPt_dipoles_magnetic3', commons=True,
width=360, height=360)
field = Field([ ['ringcurrent', {'x':0, 'y':0, 'R':R, 'phi':pi/2, 'I':1.}] ])
def f_arrows(xy):
return xy[1] * (sc.hypot(xy[0], xy[1]) / 1.4 - 1)
def f_cond(xy):
return hypot(*xy) > R and fabs(fabs(xy[0]) - 1.4) > 0.2
nlines = 13
startpoints = Startpath(field, lambda t: sc.array([R*t, 0.]),
t0=-0.8, t1=0.8).npoints(nlines)
for p0 in startpoints:
line = FieldLine(field, p0, directions='both')
doc.draw_line(line, maxdist=1, arrows_style={'at_potentials':[0.],
'potential':f_arrows, 'condition_func':f_cond, 'scale':1.2})
# draw current symbols
symb_out = doc.draw_object('g', {'id':'out_symbol',
'transform':'translate({0},0) scale({1},{1})'.format(-R, 1./doc.unit)})
symb_in = doc.draw_object('g', {'id':'in_symbol',
'transform':'translate({0},0) scale({1},{1})'.format(R, 1./doc.unit)})
for i, g in enumerate([symb_out, symb_in]):
doc.draw_object('circle', {'cx':'0', 'cy':'0', 'r':rsym, 'stroke':'none',
'fill':'#999999'}, group=g)
doc._check_whitespot()
doc.draw_object('circle', {'cx':'0', 'cy':'0', 'r':rsym,
'fill':'url(#white_spot)', 'stroke':'#000000', 'stroke-width':'3'}, group=g)
if i == 0: # dot
c_symb = etree.SubElement(g, 'circle')
c_symb.set('cx', '0')
c_symb.set('cy', '0')
c_symb.set('r', '6')
else: # cross
c_symb = etree.SubElement(g, 'path')
c_symb.set('d', 'M {1},{4} L {0},{5} L {2},{3} L {0},{1} \
L {1},{0} {3},{2} L {5},{0} L {4},{1} L {6},{3} L {4},{5} L {5},{4} \
L {3},{6} L {1},{4} Z'.format(12.24, 8, 4.24, 0, -12.24, -8, -4.24))
c_symb.set('style', 'fill:#000000; stroke:none')
doc.write()
doc = FieldplotDocument('VFPt_dipoles_magnetic4', commons=True,
width=360, height=360)
field = Field([ ['coil', {'x':0, 'y':0, 'phi':pi/2, 'R':R, 'Lhalf':h, 'I':1.}] ])
def f_arrows(xy):
return xy[1] * (sc.hypot(xy[0], xy[1]) / 1.4 - 1)
def f_cond(xy):
return sc.hypot(xy[0], xy[1]) > R
nlines = 13
for iline in range(nlines):
p0 = sc.array([R * (-1. + 2. * (iline + 0.5) / nlines), 0.])
line = FieldLine(field, p0, directions='both', maxr=100)
doc.draw_line(line, maxdist=1, arrows_style={'at_potentials':[0.],
'potential':f_arrows, 'condition_func':f_cond, 'scale':1.2})
# draw solenoid
sheet_out = doc.draw_object('g', {
'transform':'translate({0},0)'.format(-R)})
sheet_in = doc.draw_object('g', {
'transform':'translate({0},0)'.format(R)})
for i, g in enumerate([sheet_out, sheet_in]):
doc.draw_object('rect', {'stroke-width':0.03, 'stroke-linejoin':'round',
'x':-0.045, 'y':-h, 'width':0.09, 'height':2*h,
'stroke':'#000000', 'fill':'#bbbbbb'}, group=g)
nsym = 12
for isym in range(nsym):
y = (h - 0.015) * (2 * (isym + 0.5) / nsym - 1)
if i == 0:
doc.draw_object('circle', {'cx':'0', 'cy':y, 'r':0.02,
'fill':'#000000', 'stroke':'none'}, group=g)
else:
doc.draw_object('path', {'d':'M -2,-2 L 2,2 M -2,2 L 2,-2',
'fill':'none', 'stroke':'#000000',
'transform':'translate(0, {0}) scale(0.012)'.format(y),
'stroke-width':'1', 'stroke-linecap':'butt'}, group=g)
doc.write()
|
Licensing
I, the copyright holder of this work, hereby publish it under the following license:
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- You are free:
- to share – to copy, distribute and transmit the work
- to remix – to adapt the work
- Under the following conditions:
- attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
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File history
Click on a date/time to view the file as it appeared at that time.
| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 16:25, 11 January 2020 | | 840 × 840 (103 KB) | wikimediacommons>Geek3 | User created page with UploadWizard |
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