[Voxx (OP)]

Alright, so if someone was able to produce an extremely powerful electromagnetic field, could that person create a field that would reflect charged particles on the outer edges of the field and charge and reflect objects that enter the stronger portions of the field?  So what i would like to know is what this field could reflect/reduce and what it cannot.  Such as maybe insulated materials such as rubber, so a rubber bullet would just pass right through the field while a ferrous bullet would stop or be redirected?  Anyone with more insight want to add on what I don't know?

[MikeS]

The Earths magnetosphere stops most harmful radiation from reaching the surface of the Earth.

I guess, if you took a projectile from a mag-lev gun and fired it back down the barrel at the same time as the gun was fired (less normal projectile), the field would maybe stop and then reverse the trajectory of the projectile.  Presumably, it would only work on metal or super-cooled objects.

[Voxx (OP)]

That's why i'm asking on Naked Science, I've been reading about this everywhere I can and I'm just trying to get a better understanding of it.  Because I mean true enough you would think it would work on only ferrous materials, but "theoretically" if you had a strong enough field could it not give a charge to things without a charge and then repel them?  Just something I'm trying to work out.

[CliffordK]

Keep in mind that steel is rarely used for bullets, although steel shot may be used for shotguns.  Lead would be affected much less by a magnetic field.

I think the best thing for dealing with steel shot would be to deflect the directionality of the projectiles.  For example, consider a strong electromagnet along the side of a passage, and then an impact absorbing material that would absorb the energy from bullets.

Your biggest issue would be to design a material that would absorb all the energy from the bullets, and the bullets would not bounce off at a very narrow angle.  Perhaps you could make the walls in the shape of a sawblade to catch the bullets that are drug towards the walls.

[InTheHeat]

Forget ferrous and non ferrous materials. Magnetic fields affect moving charges.

[Voxx (OP)]

So movement itself is charged, so a very strong electromagnet would have an effect on its trajectory?  Be it small or large depends on the mass, material, and velocity.  Correct?  Is this charge kinetic force?

[evan_au]

• Ferromagnetic materials (iron, nickel, etc) will be attracted into the strongest part of the magnetic field - right into your powerful magnet, where you would presumably place the item you are trying to protect. They also "short out" the magnetic field, weakening it.
• If you can persuade your adversary to make their projectiles out of diamagnetic materials like pyrolytic carbon or bismuth, these are repelled by a magnetic field. However, the diamagnetic effect is so weak that it would be almost useless (unless they used superconducting bullets).
• Metals passing through a magnetic field will induce eddy currents in the bullet, which slows down the bullet - this will be more effective for very conductive materials like silver and aluminium bullets, but ineffective against bullets made of electrical insulators.
• The Earth's magnetic field is not very intense, but it spreads out for many times earth's diameter. It is able to divert very light charged/ionised particles from the sun down towards the North and South Poles, but it does not divert neutral atoms.
• The most intense magnetic fields we can produce tend to be in a very small volume, which is surrounded by the large bulk of the magnetic field generator, and the thermal insulation for the superconductors inside. The magnetic field would not protect the magnet, but the bulk of the magnet would protect the volume containing the intense magnetic field!

I suggest that your best shield would be to surround the protected item by plain air, which is able to rapidly slow down bullets regardless of whether they are charged or neutral, conductive or insulators, ferromagnetic/paramagnetic/diamagnetic, etc. A bulletproof vest might also be useful...

[Voxx (OP)]

Thank you for your insight, so in short:

An Electromagnetic Force Field would work, but it would need to be very powerful and it would only divert the object if it was conductive.

What about a Static Force Field?  Is there a difference between a Static Force Field and an Electromagnetic?

[CliffordK]

I'm not sure there is a true "force field" beyond Science Fiction, at least not on a macro scale.  It may be quite different on a micro scale.

There are many substances that can slow down a bullet.  Water will also rapidly slow down a bullet, but obviously not as quickly as steel plate.

There was a Mythbusters episode about shooting watermelons, and I think it took about 2 watermelons to stop a speeding bullet.

Water is moderately diamagnetic, so potentially you could hold a bubble of water in place using a very strong magnetic field.  However, the human body is made up of a lot of water, any magnetic field that could contain and hold a couple of cubic meters of water in place would be very difficult and dangerous to try to walk through.

[JP]

Water is moderately diamagnetic, so potentially you could hold a bubble of water in place using a very strong magnetic field. 

Or a frog:

[Pmb]

Alright, so if someone was able to produce an extremely powerful electromagnetic field, could that person create a field that would reflect charged particles on the outer edges of the field and charge and reflect objects that enter the stronger portions of the field?  So what i would like to know is what this field could reflect/reduce and what it cannot.  Such as maybe insulated materials such as rubber, so a rubber bullet would just pass right through the field while a ferrous bullet would stop or be redirected?  Anyone with more insight want to add on what I don't know?

The answer is no. The magnitude of the field strength doesn't determine the field configuration. You're asking about the outter edge of the field. There is no outter edge of an electric field. Electric fields go on forever.

All electric fields reflect charges so I don't understand your question for the most part. The title is about a force field. There is no such thing and there can be no such thing. That only appears in movies and TV.

[Voxx (OP)]

It is true that there is no such thing as a force field, but there is the beginnings of such technologies developed by the Israeli's.  See ---> http://www.youtube.com/watch?v=D2BLphR8qgA

So, it is possible and I'm not sure if the defense is an electromagnetic force field; but it does sound energy based.

So my question is, if you could "theoretically" generate enough static force in a field or electromagnetic force could you deflect objects similar to that in the youtube video?

Also, I believe but am not sure that from the source of an electromagnetic and/or static field it weakened the further away it is projected?  Correct?  That is what I was trying to get across.  The objects that are thrown into the "outer edges" of this field have its effect and a stronger effect is caused closer to the source generation.

[Pmb]

Just because someone is researching it it doesn't mean its possible

[JP]

Trophy tracks an RPG with radar and then essentially fires a shotgun at it.  That's not exactly a force field...

http://en.wikipedia.org/wiki/Trophy_(countermeasure)

[Voxx (OP)]

True enough, from what we know of the weapon it does fire shotgun type interception projectiles.

Although, yes just because they are researching it doesn't mean it is possible, but i could say the same thing with sliding glass doors.  If your remember those olden science fiction movies they didn't have automatic sliding doors, they had someone on the other side of them using a mechanism that would open and close them.  Yes it is a rather simple example, but the same could be said for lasers.  Just because we don't know how to do it now doesn't mean its impossible, just look at what stem cell research has come up with lately.

So from a knowledgeable science fact stand point, what I'm asking "at this time," is impossible?

[JP]

I think the answer you got at the start sums it up.  You could in theory deflect certain types of materials with a really strong electromagnetic field.  For example, ferromagnetic materials or diamagnetic materials as discussed above.  If you want to deflect electrons, you need only sit next to a big negative charge.  In practice, bullets and most projectiles will have a ton of energy and momentum, and won't be strongly interacting with EM fields, so you probably can't build a practical field-based device that would be useful at deflecting them. 

I'm not sure what you mean when you talk about a "static" force field, but the only practical fields we can project to have any effect on projectiles are electromagnetic fields.  Of the other forces, gravity is too weak to use, and the nuclear forces act on too small a scale to be useful here.

[Voxx (OP)]

Hm, take a look at these and tell me what you think.

http://en.wikipedia.org/wiki/Static_forces_and_virtual-particle_exchange

I know this one is a bit out there, but ---> http://amasci.com/weird/unusual/e-wall.html

Btw, I found this quite interesting ---> http://www.youtube.com/watch?v=QGytW_C6hR8&feature=related

[JP]

Ah.  Well in that case, static and dynamic forces are just two aspects of the same thing.  When we say electromagnetic force, we mean a force that may be changing in time (and be dynamic) or may be stationary in time (static).  Fields that are changing in time tend to radiate energy away, so they might not be the "force field" you talked about, but they're still a manifestation of the same underlying force. 

In other words, if electromagnetism can't provide a force field, then static electromagnetic fields can't either.

That last video is really cool.   It reminds me of a neat experiment you can do at home fairly easily.  What you need is a length of copper pipe and a fairly strong magnet that can fit in the pipe (neodynium magnets work well).  If you hold the pipe vertically so that you can drop the magnet straight down the center, you'll notice that the magnet slows down when falling through the pipe, as if its resisting gravity.  What's actually happening is similar to what's going on in that video: the magnetic field causes current to flow in the copper pipe, and that current generates a field of its own which lifts the magnet against gravity, slowing it down. 

[Voxx (OP)]

So then plain magnets that were being fueled with a large amount of electricity couldn't repel objects?  =\  I thought it could have an effect if it could levitate a strawberry.  (I know a strawberry isn't an explosion, but the principled stands doesn't it?)  Or would the velocity bypass the magnetic push?

[JP]

You can levitate diamagnetic objects, which is a particular class of objects, with a strong magnetic field (see the frog video I posted above, or CliffordK's discussion of water).  This kind of field wouldn't levitate all matter (it would suck in ferromagnetic objects, for example).