File:VFPt dipole animation.gif
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VFPt_dipole_animation.gif (220 × 220 pixels, file size: 863 KB, MIME type: image/gif, looped, 100 frames, 5.0 s)
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Summary
[edit]DescriptionVFPt dipole animation.gif |
English: Dipol fieldlines animation. A transformation from a point-shaped dipol to a finite-size electric dipole and a finite-size magnetic dipole is shown. |
Date | |
Source | Own work |
Author | Geek3 |
Other versions | |
GIF development InfoField | This plot was created with VectorFieldPlot. |
Source code InfoField | Python codemkdir anims
./vectorfieldplot.py
# paste this code at the end of VectorFieldPlot 1.2
frames = 100
d = 0.35 # animation amplitude
r = 7.5 # charge radius
# iterate frames
for i in range(frames):
doc = FieldplotDocument('VFPt_dipole_animation_{0:0>2}'.format(i),
commons=True, width=220, height=220, unit=100)
a = abs(sin(i*2*pi/frames) * 0.75 - 0.25 * sin(3.0 * i*2*pi/frames))
if i == 0 or i == frames / 2:
# pointlike dipole
field = Field({'dipoles':[[0,0,1,0]]})
elif i < frames / 2:
# electric dipole
field = Field({'monopoles':[[-d*a,0,-0.5/(d*a)], [d*a,0,0.5/(d*a)]]})
doc.draw_charges(field, scale=r/14)
else:
# magnetic dipole
field = Field({'ringcurrents':[[0,0,0,d*a,1]]})
doc.draw_currents(field, scale=r/14)
if d * a < r / doc.unit:
# draw dipole symbol
symb = doc.draw_object('g', {'id':'dipole_symbol',
'transform':'scale({0},{0})'.format(
sqrt(1.0/doc.unit**2-(d*a/r)**2))})
defs = doc.draw_object('defs', {}, group=symb)
spot = doc.draw_object('radialGradient', {'id':'light_spot',
'cx':'0.65', 'cy':'0.7', 'r':'0.75'}, group=defs)
for col, of in [['#fff', '0'], ['#ddd', '0.15'],
['#aaa', '0.7'], ['#444', '1']]:
doc.draw_object('stop', {'stop-color':col, 'offset':of}, group=spot)
doc.draw_object('circle', {'cx':'0', 'cy':'0', 'r':str(r),
'style':'fill:url(#light_spot); stroke:#000000; stroke-width:1'}, group=symb)
doc.draw_object('path', {'style':'fill:#000000; stroke:none',
'd':'M -4,1 H 0 V 4 L 5,0 L 0,-4 V -1 H -4 V 1 Z'}, group=symb)
n = 20
# iterate fieldlines
for j in range(n):
t = -1.0 + 2.0 * (j + 0.5) / n
y = 0.25 * ((t-1)**-2 - (t+1)**-2) - 0.3*t
dy = 0.0
sf = None
if i > frames / 2:
dy = (y / abs(y) * d * a) * (1.0 - t**2)
sf = [lambda p:-p[0], lambda p:p[0]]
line = FieldLine(field, [0, y + dy],
directions='both', maxr=1e4, maxn=2e4,
stop_funcs=sf)
doc.draw_line(line, linewidth=1.0,
arrows_style={'dist':1.25, 'scale':1.1, 'max_arrows':2})
doc.write(filename='anims/' + doc.name)
|
for i in anims/*.svg; do rsvg -w1760 -h1760 $i $(echo $i | sed s/svg/png/) && convert -scale 220x220 $(echo $i | sed s/svg/png/) $(echo $i | sed s/svg/gif/); done gifsicle -d5 -l0 --colors 256 --comment "https://commons.wikimedia.org/wiki/File:VFPt_dipole_animation.gif" anims/*.gif > VFPt_dipole_animation.gif
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[edit]I, the copyright holder of this work, hereby publish it under the following licenses:
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled GNU Free Documentation License.http://www.gnu.org/copyleft/fdl.htmlGFDLGNU Free Documentation Licensetruetrue |
This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
- 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.
- share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.
You may select the license of your choice.
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Date/Time | Thumbnail | Dimensions | User | Comment | |
---|---|---|---|---|---|
current | 19:59, 2 October 2010 | 220 × 220 (863 KB) | Geek3 (talk | contribs) | own work |
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