How do TOKAMAK's provide thermal insulation

In summary, for current fusion technology, the plasma is contained using magnetic fields. Despite reaching temperatures of 100,000 degrees or higher, the plasma does not melt anything on Earth due to the macroscopic definition of temperature and the energetic neutrons only occasionally hitting the reactor walls. Magnetic fields are imposed on the outside of the plasma, causing the particles to rotate and exclude the fields. This results in lower magnetic fields and a preference for particles to move to the interior. The plasma also has a very low density compared to solid materials, and energy is radiated in the form of photons. Therefore, the first wall of the reactor needs to be cooled to prevent damage.
  • #1
Ian_Brooks
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For current fusion technology the method for containing the plasma is with magnetic fields. However the plasma reaches temperatures of 100,000 degrees+ that would melt anything on Earth -

so how do these super concentrated magnetic field provide thermal insulation?
 
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  • #2
The plasma reaching such high temperatures is really just because of our macroscopic definition of temperature. A 100 million degree tokamak plasma isn't going to melt stuff the same way a 100 million degree lump of normal material would, it just means that very energetic neutrons will occasionally hit the walls of the reactor. Making a material that can stand such collisions for a long period of time is currently an active area of research.
 
  • #3
Ian_Brooks said:
For current fusion technology the method for containing the plasma is with magnetic fields. However the plasma reaches temperatures of 100,000 degrees+ that would melt anything on Earth -

so how do these super concentrated magnetic field provide thermal insulation?
Charged particles move in small circular trajectories around magnetic field lines when their velocities are perpendicular to the magnetic fields. The magnetic fields are imposed on the outside of the plasma, and the plasma excludes the magnetic fields by virtue of the rotating particles producing magnetic fields opposite the fields which cause them to rotate. Therefore the magentic field is lower and the particles (ions and electrons) tend to preferentially move to the interior. Neutral atoms do pass through magnetic fields, but their flux is kept as low as possible.

The plasmas has very low density ~ 1014 ions-electrons/cm3, as compared to solid materials with atomic densities on the order of 1022/cm3. The energy leaking to the confinement chamber is very low.

Energy is also radiated in the form of photons via cyclotron radiation, recombination, and bremsstrahlung, so the first wall needs to be cooled.
 

1. What is a TOKAMAK and how does it generate energy?

A TOKAMAK is a type of nuclear fusion reactor that uses powerful magnetic fields to contain and heat plasma to extremely high temperatures. This causes the atoms in the plasma to collide and fuse, releasing energy in the form of heat and light.

2. How does a TOKAMAK provide thermal insulation?

A TOKAMAK uses a combination of magnetic fields and specialized materials to provide thermal insulation. The magnetic fields confine the hot plasma, preventing it from coming into contact with the walls of the reactor, while the materials used in the reactor walls are designed to withstand the extreme temperatures and prevent heat from escaping.

3. What are the advantages of using a TOKAMAK for thermal insulation?

One of the main advantages of using a TOKAMAK for thermal insulation is its ability to contain and heat plasma to extremely high temperatures, which is necessary for nuclear fusion reactions to occur. Additionally, the magnetic fields used in a TOKAMAK are adjustable, allowing for better control and stability of the plasma and resulting in more efficient energy production.

4. Are there any challenges in using a TOKAMAK for thermal insulation?

Yes, there are several challenges in using a TOKAMAK for thermal insulation. One of the main challenges is creating and maintaining the powerful magnetic fields needed to contain the plasma, which requires a significant amount of energy. Additionally, the materials used in the reactor walls must be able to withstand the extreme temperatures and radiation, which can be difficult to achieve.

5. How is the thermal insulation in a TOKAMAK being improved?

Scientists and engineers are constantly working to improve the thermal insulation in TOKAMAK reactors. This includes developing stronger and more heat-resistant materials, as well as finding ways to reduce the energy needed to maintain the magnetic fields. Additionally, advancements in technology and research are helping to improve the overall efficiency and effectiveness of TOKAMAKs as a source of energy.

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