Spherical Boundary Displace Current

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SUMMARY

The discussion focuses on calculating the total displacement current emanating from a spherical surface with a radius of 1 meter, centered at the origin, under the influence of a time-varying current I flowing along the y-axis. Participants emphasize the application of Ampere’s law and the uniqueness of magnetic field circulation to derive the displacement current. Key concepts include the relationship between electric field (E), magnetic field (B), and displacement field (D), as well as the use of Stokes' theorem to facilitate calculations. The problem requires clarification on whether the spheres are conductive or dielectric to apply boundary conditions effectively.

PREREQUISITES
  • Understanding of Ampere’s law and its application in electromagnetic theory.
  • Familiarity with Maxwell's equations, particularly the relationship between E, B, and D fields.
  • Knowledge of Stokes' theorem and its relevance in vector calculus.
  • Concept of displacement current and its significance in non-conductive media.
NEXT STEPS
  • Study the application of Ampere’s law in time-varying fields.
  • Learn about Maxwell's equations and their implications in electromagnetic theory.
  • Research Stokes' theorem and its applications in calculating integrals over vector fields.
  • Explore the concept of displacement current in detail, particularly in dielectric materials.
USEFUL FOR

This discussion is beneficial for physics students, electrical engineers, and anyone studying electromagnetic theory, particularly those interested in the behavior of electric and magnetic fields in varying conditions.

superspartan9
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Homework Statement




A current I is flowing along the y-axis and a
spherical surface with radius 1 m has its center at
origin, as in the figure left. A closed contour C is
chosen as in the figure, which is a boundary
between two semi-sphere surfaces S1 and S2. Based
on the uniqueness of magnetic field circulation (Closed line integral of)
H dot dl calculated from both surfaces S1 and S2,
find the total displacement current emanating from
the spherical surface using the Ampere’s law.

Homework Equations



No idea

The Attempt at a Solution



Not even sure where to start because it isn't clear whether these are conductive spheres or dielectric spheres. Once I figure that out, I could use the boundary conditions somehow... I honestly have no idea how to start this problem.
 

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Well, maybe I can at least give you an idea or two.

First, current i must be time-varying, or nothing happens electric-field-wise.

Second: using Ampere, write an expression for B around the wire, including the space defined by the two hemispheres. BTW the hemispheres are just geometrically descriptive surfaces. They have no material meaning. Least that's what I assume.

Third: now you have B(x,y,z). What is the Maxwell relation that relates E to B?

Fourth: what is the relation between E and D? Assume non-conducting medium.

Fifth: What is the meaning of "displacement current emanating from the spherical surface", given D and the surfaces? Think of an analogy with how you get from conduction current density J to conduction current in the Maxwell relation relating B to J and D.

Sixth: how can you apply Stokes' theorem in conjunction with item 3 to calculate item five?

No guarantees her, maybe you'll discover something along the way I didn't.
 
Last edited:

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