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Initially this question was going to be on how to improve the Parker Solar Probe shield. While time passed I saw other possibilities for using this method for active shielding.

Could a shield heated by the Sun be a liquid stabilized into a semi-solid by applying artificial magnetic field thus increasing the thermal equilibrium threshold of the metal in a liquid state?

Could an alloy of hot or cold liquid metal be made to work like magnetic putty or oil (shown below) to make a metal semisolid shield for space travel? For example put iron powder in molten lead to have the same effect as in the last 2 pictures.

Micrometeorites would leave damage to the hard metal when cold. The metal shield then would be exited by induction to melt the area then repaired by an applied magnetic field.

enter image description here https://www.geek.com/geek-cetera/this-is-how-you-melt-metal-with-magnets-1544652/ Shows how hot liquid metal can still have magnetic properties.

enter image description here

Ferrofluid Source: Reddit Oil firming from applying artificial magnetic field.

enter image description here Tumblr

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closed as unclear what you're asking by called2voyage Feb 11 at 13:33

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

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    $\begingroup$ Just read wikipedia about the Curie point Liquid iron is not magnetic. $\endgroup$ – Uwe Dec 30 '18 at 22:00
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    $\begingroup$ @Uwe: Seems OP is confusing "not magnetic" with "not ferromagnetic (but possibly paramagnetic or diamagnetic)" $\endgroup$ – Ben Voigt Dec 30 '18 at 22:10
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    $\begingroup$ @Muze Liquid iron is not ferromagnetic. An external magnetic field would not change this. $\endgroup$ – Uwe Dec 30 '18 at 22:36
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    $\begingroup$ Surely this question would be a better fit over on Physics? $\endgroup$ – Alex Hajnal Dec 31 '18 at 8:18
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    $\begingroup$ Could you mix iron with something ferromagnetic to make a ferromagnetic alloy which would behave like a ferromagnetic material when in liquid form? (Ferromagnetic is a fun word to say). $\endgroup$ – Magic Octopus Urn Dec 31 '18 at 16:11
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Could liquid metal be made ferromagnetic by externally inducing an internal magnetic field?

No. Metal is either ferromagnetic or not; this is a result of the quantum-mechanical interaction of neighbouring atoms in the metal's crystal lattice. Even non-magnetised iron at room temperature is ferromagnetic, only, the Weiss domains are randomly oriented and mostly cancel out, which can be changed by applying an external field to orient them all in the same direction. Most other metals aren't ferromagnetic and an external field can't do anything about this: there are no magnetic domains that you could align in some way. And as Uwe commented, even the ferromagnetic metals are only ferromagnetic below the Curie temperature. This always lies below the melting point, so no: liquid metals can not be made ferromagnetic.

Regarding ferrofluids: yes, those are ferromagnetic liquids, but they aren't liquid metals. In vacuum, the carrier would quickly freeze and/or evaporate.

But I don't think that's really what you meant to ask anyway: ferromagnetism is not the only way metals can interact with magnetic fields. There are three other mechanisms:

  • Paramagnetism is similar to ferromagnetism, except you don't have mesoscopic magnetic domains that could be aligned, but only microscopic spins of single atoms or molecules. Thus, paramagnets are attracted to magnets similarly as ferromagnets are, just much weaker.
    Many materials are paramagnetis, including liquids. Often they aren't metals, e.g. liquid oxygen is an example.
  • Diamagnetism is even weaker, and has the opposite effect: diamagnets are repelled by an inhomogeneous magnetic field.
  • Induction. Any conductor, and thus any metal even if liquid, will respond to a time-variable magnetic field: such a field generates currents, and those currents will broadly speaking reject the field-change. And this can indeed be used to move/shape the conductor without touching it. It is mostly important for plasma (conductive gas), and is the working principle behind Tokamak and Stellarator fusion reactors.

So, induction is your best bet. Could this be used to form a shield? Possibly. In fact fluid conductors have a natural tendency to form sheet-like structures. Whether this is practical is dubious, but it's in principle a worthwhile idea.

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  • $\begingroup$ If you look in the first picture that melted metal is being heated ans suspended with a magnet field. If a field could heat metal then it can cool it and possibly shape it like the second picture. The magnetic field is being produced from behind the heat shield.through the 1 layer of metal with a higher melting point allowing the second molten layer metal to stay fixed to the first layer via magnetic field? $\endgroup$ – Muze Jan 13 at 4:20
  • $\begingroup$ Don't understand what you're asking there. Perhaps you should flesh this out to a new question on physics.SE, for discussing details of a specific setup you propose. $\endgroup$ – leftaroundabout Jan 13 at 7:40

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