Superconductor ring: shielding currents in different directions

In summary, the conversation discusses the direction of outer and inner wall currents in a photo and how they are affected by an applied magnetic field. The speaker questions why the currents are in different directions and also asks about the relationship between rotB and j_s. They later realize their initial assumption was incorrect and that there is not a continuous magnetic field present in the photo.
  • #1
annaphys
69
1
In this photo you see on the right-hand side that the outer wall current is negative and the inner wall current is positive. That is, they are directed in different directions. But if the applied magnetic field is in the z direction as shown, then shouldn't they both be in the same direction do to the fact that j_s = -j = rotB? That is the shielding current goes in the opposite direction of the current caused by the magnetic field. Why is it so that the currents are in different directions?
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  • #2
Another question, why is rotB=mu*j_s? Shouldn't j_s would against the magnetic field so it should that rotB= mu*j where j = -j_s?
 
  • #3
Nevermind I understand it. My assumption from the beginning was wrong. There isn't a continuous homogeneous mag field in the photo just the trapped field.
 

FAQ: Superconductor ring: shielding currents in different directions

What is a superconductor ring?

A superconductor ring is a circular loop made of a material that has zero electrical resistance when cooled below a certain temperature, known as the critical temperature. This allows for the flow of electrical current without any energy loss.

How does a superconductor ring shield currents in different directions?

A superconductor ring has the ability to shield electrical currents in different directions due to the Meissner effect. When a magnetic field is applied to the ring, the superconducting material expels the magnetic field, creating a region of zero magnetic field inside the ring. This prevents any external magnetic fields from penetrating the ring and interfering with the current flow.

What are the practical applications of a superconductor ring?

Superconductor rings are used in a variety of applications, including MRI machines, particle accelerators, and high-speed trains. They are also used in research to study the behavior of superconductors and their potential for use in energy-efficient technologies.

What are the challenges in creating a superconductor ring?

The main challenge in creating a superconductor ring is the need for extremely low temperatures. Most superconducting materials require temperatures close to absolute zero (-273.15°C) to achieve their superconducting state. This requires specialized equipment and techniques to maintain these low temperatures.

Are there any potential drawbacks to using a superconductor ring?

One potential drawback of using a superconductor ring is the high cost of producing and maintaining the low temperatures required for its operation. Additionally, the superconducting state is very delicate and can be easily disrupted, making the ring susceptible to damage. However, ongoing research and advancements in technology are working towards addressing these challenges.

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