File:VFPt charged-wires octopole absE.svg
Original file (SVG file, nominally 600 × 600 pixels, file size: 255 KB)
Captions
Summary
[edit]DescriptionVFPt charged-wires octopole absE.svg |
English: Electric field around eight infinitely long charged wires with alternating charges. This configuration may be used as a octopole guide for low-field seeking particles. The background color map shows the absolute field strength, which has a minimum in the center. |
Date | |
Source | Own work |
Author | Geek3 |
SVG development InfoField | This plot was created with VectorFieldPlot. |
Source code InfoField | Python code# paste this code at the end of VectorFieldPlot 3.1
# https://commons.wikimedia.org/wiki/User:Geek3/VectorFieldPlot
doc = FieldplotDocument('VFPt_charged-wires_octopole_absE',
width=600, height=600, commons=True)
nw = 8
r = 2.0
a0 = pi/8
rods = [{'x':r * cos(2*pi*i/nw + a0), 'y':r * sin(2*pi*i/nw + a0),
'q':1 - 2 * (i % 2)} for i in range(nw)]
field = Field([ ['charged_wire', rod] for rod in rods])
doc.draw_charged_wires(field, scale=2)
spath = Startpath(field, lambda t: sc.array([
r * cos(a0) + r * sin(pi/nw) * cos(2*pi*t + a0),
r * sin(a0) + r * sin(pi/nw) * sin(2*pi*t + a0)]), t0=0.0, t1=1)
nl = 20
for i in range(nl):
a = (i + 0.5) / nl
if (i + ((2 * i) // nl)) % 2 == 1:
offs = 1.2
else:
offs = 0.7
for m in range(0, nw, 2):
line = FieldLine(field, rot(spath.startpos(a), 2*pi*m/nw),
directions='both')
doc.draw_line(line, linewidth=2.4, arrows_style={'dist':0.9,
'scale':1.2, 'offsets':[offs, 0.4, 0.4, offs], 'max_arrows':3})
def absE(xy):
return vabs(field.F(xy))
def path(R, phi):
return rot([r, 0], a0) + rot([R,0], a0 + phi)
E0 = -sc.optimize.minimize(lambda phi: -absE(path(0.3, phi)), 1).fun
E1 = -sc.optimize.minimize(lambda phi: -absE(path(0.295, phi)), 1).fun
doc.draw_scalar_field(func=absE, cmap=doc.cmap_WtGnBu, vmin=0, vmax=E0)
doc.draw_contours(func=absE, linewidth=1, linecolor='#111111',
levels=sc.linspace(0, E1, 11)[:-1], attributes={'opacity':'0.7'})
doc.write()
|
Licensing
[edit]- 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.
File history
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Date/Time | Thumbnail | Dimensions | User | Comment | |
---|---|---|---|---|---|
current | 17:46, 4 June 2020 | 600 × 600 (255 KB) | Geek3 (talk | contribs) | Uploaded own work with UploadWizard |
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Metadata
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Short title | VFPt_charged-wires_octopole_absE |
---|---|
Image title | VFPt_charged-wires_octopole_absE
created with VectorFieldPlot 3.1 https://commons.wikimedia.org/wiki/User:Geek3/VectorFieldPlot about: https://commons.wikimedia.org/wiki/File:VFPt_charged-wires_octopole_absE.svg rights: Creative Commons Attribution ShareAlike 4.0 |
Width | 600 |
Height | 600 |