File:VFPt Dipole field.svg

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Original file (SVG file, nominally 700 × 600 pixels, file size: 39 KB)

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Summary

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Description
English: Schematic dipole field around the earth. (monochromatic)
Date
Source Own work
Author Geek3
Other versions Dipole field.svg
SVG development
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The SVG code is valid.
 
This plot was created with VectorFieldPlot.
 
This file uses embedded text.
Source code
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Python code

# paste this code at the end of VectorFieldPlot 1.3
doc = FieldplotDocument('VFPt_Dipole_field', commons=True, width=700, height=600, unit=100)
R = 1.55
sca = 2.4; lw = 1.0
field = Field({'dipoles':[[0, 0, 0, -1]]})
F = lambda t: sc.dot(field.F([R*cos(t), R*sin(t)]), [cos(t), sin(t)])
Fi = lambda t1: ig.quad(F, 0, t1)[0] * R
Fsum = Fi(pi)
line = FieldLine(field, [0, 5], directions='forward', maxr=10)
doc.draw_line(line, linewidth=lw, arrows_style={'dist':6-2*R, 'scale':sca,
    'max_arrows':2, 'min_arrows':2, 'fixed_ends':[False, True, True, False]})
n = 15
p = -0.3
for i in range(n):
    a = (i + 0.5 + p) / (n + 2*p)
    t = op.brentq(lambda t:Fi(t) - a*Fsum, 0, pi)
    if abs(i - n/2) > 4:
        line = FieldLine(field, [R*cos(t), R*sin(t)], directions='both')
        doc.draw_line(line, linewidth=lw, arrows_style={'dist':2*R, 'scale':sca,
        'max_arrows':2, 'min_arrows':1, 'fixed_ends':[True, False, False, True]})
    elif (i != 7):
        line = FieldLine(field, [R*cos(t), R*sin(t)], directions='both', maxr=3)
        doc.draw_line(line, linewidth=lw, arrows_style={'dist':2*R, 'scale':sca,
        'max_arrows':1, 'min_arrows':1, 'fixed_ends':[False, False, False, True]})
        line = FieldLine(field, [R*cos(t), -R*sin(t)], directions='both', maxr=3)
        doc.draw_line(line, linewidth=lw, arrows_style={'dist':2*R, 'scale':sca,
        'max_arrows':1, 'min_arrows':1, 'fixed_ends':[True, False, False, False]})
n2 = 3
for j in [-1,1]:
    for i in range(n2):
        a = (i + 0.5 - p) / (n + 2*p)
        t = op.brentq(lambda t1: ig.quad(lambda r:field.F([r, 0.])[1], R, t1)[0] - a*Fsum, 0.1, R)
        line = FieldLine(field, [j*t, 0.], directions='both')
        doc.draw_line(line, linewidth=lw, arrows_style={'dist':2*R, 'scale':sca,
            'max_arrows':1, 'min_arrows':1})
Re = 0.855
earth = doc.draw_object('g', {'id':'earth'})
doc.draw_object('circle', {'r':Re, 'cx':'0', 'cy':'0',
    'style':'fill:#ffffff; stroke:#000000; stroke-width:0.01'}, group=earth)
doc.draw_object('path', {'d':'M -{0},0 A {0},{1} 0 0 1 {0},0'.format(Re, 0.2*Re),
    'style':'fill:none; stroke:#000000; stroke-width:0.01'}, group=earth)
text_N = doc.draw_object('text', {'text-anchor':'middle', 'x':'0', 'y':37,
    'transform':'translate(0,0.7) scale(0.002,-0.002)',
    'style':'fill:#000000; stroke:none; font-size:100px; font-family:Bitstream Vera Sans'})
text_N.text = 'N'
text_S = doc.draw_object('text', {'text-anchor':'middle', 'x':'0', 'y':37,
    'transform':'translate(0,-0.7) scale(0.002,-0.002)',
    'style':'fill:#000000; stroke:none; font-size:100px; font-family:Bitstream Vera Sans'})
text_S.text = 'S'
doc.write()

Licensing

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I, the copyright holder of this work, hereby publish it under the following licenses:
GNU head 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.
w:en:Creative Commons
attribution share alike
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.

File history

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Date/TimeThumbnailDimensionsUserComment
current22:44, 13 December 2010Thumbnail for version as of 22:44, 13 December 2010700 × 600 (39 KB)Geek3 (talk | contribs)own work

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