File:VFPt four magnets.svg

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Original file ‎(SVG file, nominally 800 × 800 pixels, file size: 77 KB)

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Summary[edit]

Description
English: Drawing of four homogeneously magnetized cylindrical magnets of different aspect ratios with exactly computed magnetic field lines. The magnetic north poles are aligned on top and the magnetic south poles on the bottom, with magnetization along the cylinder axes. The cylinder dimensions are:
, , ,
Date
Source Own work
Author Geek3
SVG development
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The SVG code is valid.
 
This plot was created with VectorFieldPlot.
Source code
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Python code

# paste this code at the end of VectorFieldPlot 2.4
RL = [ [0.1, 1.], [0.4, 0.7], [0.7, 0.4], [1.0, 0.1] ]

for i, (R, L) in enumerate(RL):
    doc = FieldplotDocument('VFPt_four_magnets' + str(i+1), commons=True,
        width=380, height=380)
    
    field = Field([ ['coil', {'x':0, 'y':0, 'phi':pi/2,
        'R':R, 'Lhalf':L, 'I':2.*L}] ])
    field_pot = Field([
        ['charged_disc', {'x0':-R, 'x1':R, 'y0':L, 'y1':L, 'Q':pi*R**2}],
        ['charged_disc', {'x0':-R, 'x1':R, 'y0':-L, 'y1':-L, 'Q':-pi*R**2}] ])
    
    nlines = 11
    V0 = field_pot.V([0., 1.9 * 0.6 + 0.4 * L])
    for iline in range(nlines):
        p0 = sc.array([R * (2. * (iline + 0.5) / nlines - 1.), 0.])
        line = FieldLine(field, p0, directions='both', maxr=100)
        arrow_potentials = [0.]
        if iline > 0 and iline < nlines -1:
            arrow_potentials += [-V0, V0]
        doc.draw_line(line, maxdist=1,
            arrows_style={'at_potentials':arrow_potentials,
                'potential':field_pot.V,
                'condition_func':lambda xy: fabs(xy[0])>R or fabs(xy[1])>L})
    
    doc.draw_magnets(field)
    doc.draw_object('rect', {'x':'-1.9', 'y':'-1.9', 'width':'3.8',
        'height':'3.8', 'style':'fill:none; stroke:#aaaaaa; stroke-width:0.03;'})
    
    doc.write()

Licensing[edit]

I, the copyright holder of this work, hereby publish it under the following license:
w:en:Creative Commons
attribution share alike
This file is licensed under the Creative Commons Attribution-Share Alike 4.0 International license.
You are free:
  • to share – to copy, distribute and transmit the work
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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.

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Date/TimeThumbnailDimensionsUserComment
current13:09, 1 November 2019Thumbnail for version as of 13:09, 1 November 2019800 × 800 (77 KB)Geek3 (talk | contribs)User created page with UploadWizard

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