Can Superconductors Reach Relativistic Speeds and Emit Synchrotron Photons?

In summary, currents can be injected into a superconductor using low-voltage DC power supplies or by energizing a superconducting coil and shorting the ends. However, as the current increases, the superconductor will eventually lose its superconducting properties due to the magnetic field created. This happens before the electrons reach relativistic speeds. It is not about the velocity of the current, but the number of electrons moving in a preferred direction. In a superconducting state, no electromagnetic radiation can be emitted due to the lack of resistance.
  • #1
sol47739
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TL;DR Summary
I have some questions about superconductors
How are currents injected into a superconductor? And can you regulate the velocity of the current afterwards? Since the magnetic field can’t penetrate?

What would happen if you tried to make the Cooper pairs approach relativistic speeds? Would the superconductor stop being in its superconducting state? Or would it be possible, and in case it would be possible would the Cooper pairs emit synchrotron photons?
 
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  • #2
sol47739 said:
Since the magnetic field can’t penetrate?
The magnetic field can penetrate a small amount. The depth of penetration is known as the London penetration depth, though it is typically very small, on the order of nanometers. Note that a superconductor is, well, a perfect conductor. It responds very intensely to applied magnetic fields since there is no resistance to rob its charges of energy. This is the very reason it expels a magnetic field in the first place.

sol47739 said:
How are currents injected into a superconductor?
On way is to use low-voltage DC power supplies to run current through feeder wires that are attached to the superconductor. The feeder wires are very low resistance so that minimal power loss happens. Alternatively, you can energize a superconducting coil with the aforementioned DC supply and then short the two ends of the coil together with a piece superconducting wire, forming a closed, superconducting loop.

I believe you can use induction as well, since the superconductor must respond to a changing magnetic field is some fashion in order to oppose it, but I'm not certain.

sol47739 said:
What would happen if you tried to make the Cooper pairs approach relativistic speeds? Would the superconductor stop being in its superconducting state? Or would it be possible, and in case it would be possible would the Cooper pairs emit synchrotron photons?
As some point, increasing the current causes the superconductor to lose its superconducting properties due to the magnetic field created by the current. This happens well before the electrons become relativistic.
 
  • #3
Drakkith said:
The magnetic field can penetrate a small amount. The depth of penetration is known as the London penetration depth, though it is typically very small, on the order of nanometers. Note that a superconductor is, well, a perfect conductor. It responds very intensely to applied magnetic fields since there is no resistance to rob its charges of energy. This is the very reason it expels a magnetic field in the first place.On way is to use low-voltage DC power supplies to run current through feeder wires that are attached to the superconductor. The feeder wires are very low resistance so that minimal power loss happens. Alternatively, you can energize a superconducting coil with the aforementioned DC supply and then short the two ends of the coil together with a piece superconducting wire, forming a closed, superconducting loop.

I believe you can use induction as well, since the superconductor must respond to a changing magnetic field is some fashion in order to oppose it, but I'm not certain.As some point, increasing the current causes the superconductor to lose its superconducting properties due to the magnetic field created by the current. This happens well before the electrons become relativistic.
Thanks for answering! So if I understand correctly you can't make a current inside a superconductor go to fast since the magnetic field of the current will destroy the superconducting state?

If you increase the current's velocity in other words accelerate it will the superconductor emit electromagnetic radiation as normal accelerating charges would do? I fell that it won't but I am not sure, why or why not?

Is AC current possible inside a superconductor?
 
  • #4
It's not really about speed or velocity, but about numbers. The electrons in any conductor are constantly moving about in a random, unordered motion. Setting up a voltage merely makes some proportion of them move preferentially in single direction around the circuit. The stronger the voltage, the larger the current, the more electrons are moving in this preferred direction at any given time. The velocity of electrons doesn't change much (note I'm talking about the velocity of individual electrons, not the drift velocity).

My understanding is that something similar happens in a superconductor. You have an unordered motion of electrons or electron-pairs and upon having some electric or magnetic field applied some proportion of these will begin to move in a preferred direction. It's just that once the magnetic field of the current reaches some critical value it 'quenches' the superconductor, destroying the superconducting state.

sol47739 said:
If you increase the current's velocity in other words accelerate it will the superconductor emit electromagnetic radiation as normal accelerating charges would do? I fell that it won't but I am not sure, why or why not?
As long as the superconductor is in a superconducting state then no radiation can be emitted since this would require that the charges lose energy, which would show up as resistance, of which a superconductor has none while in its superconducting state. There are simply no lower energy states that the charges can move to in order to give up this energy to radiation.
 
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  • #5
sol47739 said:
Thanks for answering! So if I understand correctly you can't make a current inside a superconductor go to fast since the magnetic field of the current will destroy the superconducting state?

If you increase the current's velocity in other words accelerate it will the superconductor emit electromagnetic radiation as normal accelerating charges would do? I fell that it won't but I am not sure, why or why not?

Is AC current possible inside a superconductor?

Speed has nothing to do with it. Cooper pairs in regular superconductors do not "travel" any faster than charges in normal metal.
It seems you are under the impression that the transport in superconductors is ballistic but that is not the case. The fact that there is no DC resistance does not mean that Cooper pairs can travel any faster than regular electrons.

Also, the question about injecting currents is a bit vague. If the SC is just part of your circuit you just make contact to it in the same way as any other material.
If you are referring to persistent currents in e.g. superconducting solenoids then this is done by simply turning a short piece of the wire normal using a heater (this is known as a heat switch) ; this makes this piece resistive and you can then inject current into the solenoid. Once the solenoid is up to field (=there is enough current circulating) you can turn off the heater which becomes superconducting and therefore creates a perfect short, meaning the current start circulating only in the solenoid. Once this happens you can disconnect the cables to the solenoid if you want (more often than not they are left connected, they make no difference)

Also, sure AC is not a problem but the superconductor is no longer lossless; at high frequencies (~100s of GHZ) SC can actually be worse conductors than good metals
 
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More of.a.comment.to Drakkith's first reply. A superconductor is not merely a perfect conductor, no. It is more.than that. A perfect conductor (resistivity equals to 0) would freeze any B field inside of it if the material undergone a transition into that perfect conducting state. It would prevent the field from changing w.r.t. time. A superconductor does not behave this way, a superconductor expells any B field inside of it. A.superconductor is a very strange beast compared to an ordinary conductor, even if said conductor was idealized.
 
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There are 2.5 types of superconductor. Type I expels all magnetic fields to its surface. Type II is honeycombed with electromagnetic vortices each with one quantum of energy. These tiny votives repel one another so form a regular hexagonal lattice. With Type 1.5 the vortices attract at larger distances and repel when closer. The vortices either form small groups or have a random pattern. With Type I the vortices attract so they merge into one

It is believed that neutron star cores are type 1.5. Some gas giant cores may be superconducting metallic hydrogen.
 
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FAQ: Can Superconductors Reach Relativistic Speeds and Emit Synchrotron Photons?

1. Can superconductors reach relativistic speeds?

No, superconductors are materials that can conduct electricity without resistance, but they are limited by the speed of light. Relativistic speeds, which are speeds close to the speed of light, cannot be achieved by superconductors.

2. What is the relationship between superconductors and synchrotron photons?

Superconductors can emit synchrotron photons when they are accelerated to high speeds in a circular path. This is due to the emission of electromagnetic radiation as the particles move in a curved path.

3. Can all superconductors emit synchrotron photons?

No, not all superconductors can emit synchrotron photons. Only superconductors that are accelerated to high speeds in a circular path can emit synchrotron photons.

4. What are some potential applications of superconductors emitting synchrotron photons?

Some potential applications include using synchrotron photons for medical imaging, particle accelerators, and high-energy physics research. They can also be used in technologies such as MRI machines and particle detectors.

5. Are there any challenges to achieving superconductors emitting synchrotron photons?

Yes, there are several challenges to achieving this. One challenge is creating a strong enough magnetic field to accelerate the superconductors to high speeds. Another challenge is maintaining the superconducting state at such high speeds, as any resistance or heating can disrupt the emission of synchrotron photons.

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