Magnetic confinement and Alfven's theorem

In summary, the conversation discusses the possibility of achieving magnetic confinement of hot plasma, with the mention of Earnshaw's theorem and Alfven's theorem. While Earnshaw's theorem states that electrostatic confinement of plasma is not possible, Alfven's theorem suggests that magnetic confinement is achievable due to the magnetic flux getting 'frozen' within the plasma. The conversation also touches upon the importance of plasma being a perfectly conducting fluid in this process. The participants also clarify their understanding of the topic and conclude that magnetic confinement of hot plasma is indeed possible.
  • #1
Boltzmann2012
31
0
Hi,

I was reading about Earnshaw's theorem and how it explains the non availability of electrostatic confinement of plasma, but does Alfven's theorem really prove the fact that magnetic confinement of hot plasma is achievable?

Regards,

Boltzmann
 
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  • #3
Hey sankalpmittal,
I was actually reading Griffiths in which he states that electric confinement is not possible since a stable eq condition cannot be achieved by a space distribution of charges. According to alfven's theorem, the magnetic flux gets 'frozen' within the plasma/liquid and hence it acquires some magnetic character. Using this it can be confined.

Please tell me if I am wrong. I am a beginner.


Thanks for your help and time,

Regards,

Boltzmann
 
  • #4
Boltzmann2012 said:
Hey sankalpmittal,
I was actually reading Griffiths in which he states that electric confinement is not possible since a stable eq condition cannot be achieved by a space distribution of charges. According to alfven's theorem, the magnetic flux gets 'frozen' within the plasma/liquid and hence it acquires some magnetic character. Using this it can be confined.

Please tell me if I am wrong. I am a beginner.


Thanks for your help and time,

Regards,

Boltzmann

Yeah , you're right. Sorry about that huh. I kinda blundered it. :redface:

Ok , so Alfven's theorem states that in a perfectly conducting fluid , magnetic lines move within the fluids and at times (for example in sun which is but a very hot and churning ball of plasma) and when two bobs of plasma are connected by magnetic field at time , then they are also connected by it at all other times , for when fluid is very hot , the electrons from it are stripped off and hence its conducting , and thus the bobs of plasma are always being interacted by magnetic fields and at times , the magnetic fields are distorted and hence are frozen into the plasma. So its also known as "frozen flux theorem". But magnetic "topology" is always preserved.

So yes , the hot plasma can be confined and in other words magnetic confinement of hot plasma is achievable.

This takes place rarely (I think) when plasma isn't warm. (In my opinion its not possible in this case.)

But yes , you're right. Magnetic confinement of hot plasma is achievable by Alfven's theorem.

Hope this helps. :)
 
  • #5
Thank you very much, sankalpmittal.

Best Wishes and Regards,

Boltzmann
 

1. What is magnetic confinement?

Magnetic confinement is a method used to contain and control plasma, a state of matter in which atoms have been stripped of their electrons. It involves using magnetic fields to keep the plasma confined and away from the walls of the container.

2. How does magnetic confinement work?

Magnetic confinement works by using strong magnetic fields to trap the plasma in a specific region. The magnetic fields are created by powerful electromagnets or superconducting coils, which produce a strong and stable magnetic field that keeps the plasma confined.

3. What is Alfven's theorem?

Alfven's theorem, also known as the frozen-in theorem, states that in a plasma, the magnetic field lines move with the plasma and remain frozen in it. This means that the plasma and the magnetic field are tightly coupled and cannot move independently of each other.

4. How does Alfven's theorem relate to magnetic confinement?

Alfven's theorem is important in magnetic confinement because it helps to explain how the plasma can be confined and controlled using magnetic fields. The frozen-in nature of the magnetic field lines means that the plasma can be manipulated by changing the shape and strength of the magnetic field.

5. What are the advantages of magnetic confinement for fusion energy?

Magnetic confinement is one of the leading approaches for achieving controlled fusion reactions, which could potentially provide a clean and abundant source of energy. It offers several advantages, including the ability to control and confine the plasma for long periods of time, high plasma temperatures, and the ability to scale up the technology for larger reactors.

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