File:VFPt cylinder magnet potential+contour.svg

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Original file ‎(SVG file, nominally 800 × 800 pixels, file size: 196 KB)

Captions

Captions

Magnetic scalar potential of a cylinder magnet

Summary

[edit]
Description
English: Drawing of a homogeneously magnetized cylindrical magnet with exactly computed magnetic field lines. The cylinder has the proportions R/L=1/2. The magnetic north pole is aligned on top and the magnetic south pole on the bottom, with magnetization along the cylinder axis. The magnetic scalar potential 𝜓 is shown in the background from positive (fuchsia) through zero (yellow) to negative (aqua) together with uniformely spaced equipotential lines. Note that the field lines follow the gradient of the scalar potential.
Date
Source Own work
Author Geek3
Other versions VFPt flat cylinder magnet potential+contour.svg
SVG development
InfoField
 
The SVG code is valid.
 
This plot was created with VectorFieldPlot.
Source code
InfoField

Python code

# paste this code at the end of VectorFieldPlot 3.4
# https://commons.wikimedia.org/wiki/User:Geek3/VectorFieldPlot
doc = FieldplotDocument('VFPt_cylinder_magnet_potential+contour',
    commons=True, width=800, height=800)

R, L2 = 1., 1.
Bfield = Field([ ['coil', {'x': 0, 'y': 0, 'phi': pi/2, 'R': R, 'Lhalf': L2, 'I': 1}] ])
Hfield = Field([ ['charged_disc', {'x0':-R, 'y0':-L2, 'x1':R, 'y1':-L2, 'Q':-1}],
                 ['charged_disc', {'x0':-R, 'y0':L2, 'x1':R, 'y1':L2, 'Q':1}] ])

doc.draw_magnets(Bfield)

U0 = Hfield.V([0., L2 + 0.02])
doc.draw_scalar_field(func=Hfield.V, cmap=doc.cmap_AqYlFs, vmin=-U0, vmax=U0)
U1 = Hfield.V([0., L2])
doc.draw_contours(func=Hfield.V, levels=np.linspace(-U1, U1, 25)[1:-1])

nlines = 22
startpoints = Startpath(Bfield, lambda t: np.array([-R + 2. * R * t, 0.])
    ).npoints(nlines)
cond = lambda xy: fabs(xy[1]) < 1e-2 or fabs(xy[1]) > L2

for iline, p0 in enumerate(startpoints):
    line = FieldLine(Bfield, p0, directions='both', maxr=12)
    arrows_style = {'dist':2.0}
    if iline >= 3 and iline < nlines - 3:
        arrows_style = {'potential':Hfield.V,
            'at_potentials':[-0.46*U1, -0.12*U1, 0.12*U1, 0.46*U1],
            'condition_func':cond}
    doc.draw_line(line, linewidth=2.4, arrows_style=arrows_style)

doc.write()

Licensing

[edit]
I, the copyright holder of this work, hereby publish it under the following license:
w:en:Creative Commons
attribution
This file is licensed under the Creative Commons Attribution 4.0 International 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.

File history

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Date/TimeThumbnailDimensionsUserComment
current14:47, 20 June 2024Thumbnail for version as of 14:47, 20 June 2024800 × 800 (196 KB)Geek3 (talk | contribs)Uploaded own work with UploadWizard

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