Plasma and Magnetic Fields: A Perpetual Motion Conundrum?

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Discussion Overview

The discussion revolves around the behavior of plasma in magnetic fields, particularly in the context of tokamaks and the implications for perpetual motion. Participants explore the dynamics of plasma movement, the role of magnetic fields, and the thermodynamic principles involved.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether plasma in a magnetic field could result in perpetual motion, suggesting this might violate thermodynamic laws.
  • Another participant clarifies that the motion of plasma is due to thermal motion rather than the magnetic fields, which primarily serve to confine and guide the plasma.
  • A different viewpoint introduces the concept of ferromagnetic fluids, suggesting that a particle suspension could respond to magnetic fields differently than a simple non-magnetic fluid.
  • One participant reiterates the initial question about perpetual motion, distinguishing between perpetual motion as an ongoing state (like Earth's orbit) and the concept of a perpetual motion machine that produces more energy than it consumes.
  • Another participant notes that tokamaks require significant energy input and cannot operate without energy loss, emphasizing that they cannot achieve perpetual motion in the traditional sense.
  • A final comment suggests a combination of magnetic disturbances and fluid dynamics as an interesting area for scientific exploration.

Areas of Agreement / Disagreement

Participants express differing views on the implications of plasma behavior in magnetic fields and the concept of perpetual motion. There is no consensus on whether the initial question about perpetual motion is valid or how it relates to thermodynamic principles.

Contextual Notes

Participants highlight various assumptions about the nature of plasma, magnetic fields, and energy dynamics, but these assumptions remain unresolved within the discussion.

Who May Find This Useful

This discussion may be of interest to those studying plasma physics, magnetic confinement, thermodynamics, and related experimental applications in fusion technology.

Fischer777
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I was wondering, if plasma moves moves in the same direction as a magnetic field when placed in a magnetic field, it seems that plasma would be in a perpetual state of motion if suspended inside a torus created by ring magnets, such as a tokamak. Wouldn't this violate the laws of thermodynamics, because you would essentially be creating perpetual motion? Or am I missing something?
 
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The magnets don't cause the plasma to move. The particles themselves are in motion due to thermal motion (heat). The magnetic fields merely confine and guide the plasma. If the plasma cools down too far the ions will combine with the electrons and the plasma will cease to be a plasma and turn back into a normal gas.

Particles will spiral around the magnetic field lines and will be repelled by a gradiant in the field, but other than that they magnets don't do much else.
 
You're talking about a ferromagnetic fluid yes? It'd have to be a particle suspension that could respond to an array of different charges to follow the magnetic field. A simple non-magnetic fluid would not move much because of heat unless there was a phase change involved.
 
Fischer777 said:
I was wondering, if plasma moves moves in the same direction as a magnetic field when placed in a magnetic field, it seems that plasma would be in a perpetual state of motion if suspended inside a torus created by ring magnets, such as a tokamak. Wouldn't this violate the laws of thermodynamics, because you would essentially be creating perpetual motion? Or am I missing something?

It's confusing terminology. Perpetual motion is perfectly OK -- the Earth more or less does this as it orbits the sun, for 9 billion years any way. Superflow is a perpertual flow and is also possible. A perpetual motion machine implies that it is producing more energy than it consumes, which is not possible. So they aren't the same thing.

In a tokomak there is a lot of energy going into the electromagnets. It can't be built in such a way as to not lose energy. Pull the plug and it will cool down.
 
sequenced magnetic disturbance + ferromagnetic fluid +torus or spherical shaped design = fun science.
 

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