Force Field - How would you make one?

[Realitycheck]

Ever since I read about magnetic fields used to contain hot nuclear fusion, it seems like that would be a way to go. It's just that the magnetic field would be so strong, it would interefere the running of the ship, unless the field was produced externally and the rest of the ship was insulated from it.

[swansont]

Force fields as depicted in most movies/TV shows violate the laws of physics.

[timo]

Would be interesting to have a definition of what a "force field" is supposed to be. Surely we are not talking about a defensive measure against Klingon Photon Torpedoes for a practical application.

[Realitycheck]

Force fields as depicted in most movies/TV shows violate the laws of physics.

Err, maybe it wasn't a magnetic field. How did you say that we could produce hot fusion in a lab?

[Severian]

You would need to decide what you were protecting from first. For example, a magnetic field wouldn't stop a ceramic shell.

[YT2095]

a Phalanx CIWS would

 

that would be My personal choice.

[insane_alien]

well, a magnetic field IS a force field by the scientific definition of the term. as are electric fields and gravitaional fields.

 

if you are talking about something more like the scifi versions, google 'plasma window'

[timo]

Well, a magnetic field IS a force field by the scientific definition of the term.

I'm not even that a scientific definition of the term even exists. A field is a function of space (note that function means "assigns single value to each element of the domain"). Not only do you get a dependence on the charge of the particle when considering the force due to an electric or gravitational field, in the case of the magnetic field you also get a dependance on the velocity .

[insane_alien]

oh... the way i understood back in phyisic was that a field of a force was a force field. must just have been the way it was explained to me.

[timo]

Sure, that would have been my understanding, too. What I was saying is that I wouldn't consider F = q(v x B) a field, because in addition to position, it also depends on charge and velocity. Might be or at least sound pedantic but somehow the notion of a force field in a scientific context (as opposed to the sci-fi meaning that is certainly meant here, anyways) gives me headaches. The term sounds all-too familiar, but not from a physics context. Atm, I couldn't think of an example where the term made sense, either.

 

EDIT: I have checked the index of 5 books that could potentially know the term. Only one of the books had the term indexed. It sais:

Force Fields

If a force on a mass point only depends on its position r (and possibly from time but not e.g. from its velocity [math]\dot r[/math]), in other words if F=F®, then we say that in the respective area of space there is a force field F®.

[swansont]

There are two divergent things being discussed. Real forces and fields, and ones that would allow "running of the ship" which (to me) implies some kind of protective system that keeps everything out. It's rather ill-defined.

 

So, which is it?

[Realitycheck]

Something that would repel matter/energy around the hull of a spaceship. An invisible wall used to contain nuclear fusion would probably do the trick.

[Sisyphus]

I have a force field, of sorts. My mass distorts the spacetime around me, resulting in a de facto attractive force that seems to work on all matter. I haven't decided what to call it yet.

[iNow]

Musk?

[YT2095]

Something that would repel matter/energy around the hull of a spaceship. An invisible wall used to contain nuclear fusion would probably do the trick.

 

not really, I`ll bet you I could fire a pea out of a straw through that field!

[Klaynos]

not really, I`ll bet you I could fire a pea out of a straw through that field!

 

Unless you charged it....

 

They're also over rather small areas, take ALOT of energy, and are continuous...

 

So nothing like you'd get in <insert popular SciFi here>

[swansont]

Something that would repel matter/energy around the hull of a spaceship. An invisible wall used to contain nuclear fusion would probably do the trick.

 

It works for fusion because it's a plasma.

[Psyber]

You would need to decide what you were protecting from first. For example, a magnetic field wouldn't stop a ceramic shell.

Or even a good old fashioned lead one.

[foodchain]

Could you use some sort of super cooled condensate like a BEC to shield against gamma radiation? I mean if a BEC can interact with light as to slow it(how?) could a BEC basically do the same to gamma radiation then?

[swansont]

Could you use some sort of super cooled condensate like a BEC to shield against gamma radiation? I mean if a BEC can interact with light as to slow it(how?) could a BEC basically do the same to gamma radiation then?

 

A BEC will slow light that is near an absorption peak. It's a very specific condition, not a general one.