Magnetism and Reentry: Could a Halbach Array Reduce Heat?

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SUMMARY

The discussion centers on the potential application of a Halbach array of magnets in reentry vehicles to mitigate heat transfer from plasma during atmospheric reentry. Participants explore whether such an array could levitate the vehicle above the plasma, thus reducing heat exposure to the heat shield. Key considerations include the positioning of the array, the type of magnets used (permanent vs. electromagnets), and the implications of charged particles in plasma interacting with the magnetic field. The consensus indicates that while the concept is intriguing, practical challenges exist, particularly regarding the behavior of charged particles and the thermal limits of materials involved.

PREREQUISITES
  • Understanding of Halbach arrays and their applications in magnetic levitation.
  • Knowledge of plasma physics and the behavior of charged particles.
  • Familiarity with heat transfer principles in high-temperature environments.
  • Basic concepts of electromagnetism, particularly in relation to magnetic fields and forces.
NEXT STEPS
  • Research the principles of Halbach arrays and their effectiveness in magnetic levitation systems.
  • Study the physics of plasma and its interaction with magnetic fields during reentry.
  • Examine heat shield materials and their thermal limits under extreme conditions.
  • Explore the design and implementation of inductrack maglev systems for potential applications.
USEFUL FOR

Aerospace engineers, physicists, materials scientists, and anyone interested in advanced reentry vehicle design and thermal protection systems.

LURCH
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I was just wondering;

What would happen if a Halbach array of magnets were placed just beneath the heat shield on a reentry vehicle? The plasma produced by reentry is, essentially, charged particles moving at high speed. Would a Halbach array magnetically levitate the reentry vehicle away the from the plasma (IOW, recall the plasma away from the heat shield) the way it does with an inductrack maglev?

If so, would the increase in distance result in less heat being transferred to the vehicle, or with the work being done on the magnets caused them to heat up?
 
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I can't believe that no-one has responded to this. It's a very interesting question. While I've never heard of a 'Halbach array', I'm going on the assumption that it's the layout used for a typical maglev system. I'll look that up later.
I would suspect to start with that such an array would have to be above the heat shield rather than below it, to prevent it from melting. (Or did you mean 'beneath' as being in a deeper layer?)
If they're electromagnets rather than the permanent variety, they'd definitely heat up due to electrical resistance, but not to the temperature of the plasma sheath. The components would melt before that happened.
This is way beyond me, though, so I hope that someone else chirps up. I'm most interested to see what the consensus is.
 
The http://www.answers.com/topic/halbach-array").

(I should have put those links in the OP.)

I've also tried discussing the potential for this type of maglev for roller coasters (although I guess we'd have to just call it a "coaster," without the "roller"). But it's very difficult to introduce such a new idea to anyone who might be able to do something about it.
 
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While I muchly appreciate the link that you provided, I must readily admit that it is far beyond my understanding.
That having been said, I've never shied away from offering an uninformed opinion. :biggrin:
Skipping off of the plasma sheath sounds good to me in principle, as long as that sheath doesn't just shred the artificial magnetic field. It sort of seems like trying to surf a tsunami.
 
Wouldn't your array attract the charged particles as often as repel them, with no net effect?
 
mLuby said:
Wouldn't your array attract the charged particles as often as repel them, with no net effect?
I don't think that it would. A Halbach Array repels ordinary rails in an inductrack maglev. Of course, in that case, the rails are neutral whereas plasma is charged.

Perhaps just a set of permanent magnets with the positive pol facing outward?
 

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