Some time ago, I did a back-of-the-envelope calculation about magnetism, electricity, and graphene. I was (and still am) curious about developing a "deflector shield" based in known and viable science. I don't remember the exact numbers I used, but my calculations indicated that passing a unit charge through a certain length of graphene would produce a magnetic field capable of exerting enough force at a 30-foot (9.1-meter) radius to deflect or stop an inbound missile traveling at about Mach 2.5, which appears to be on the slow end of air-to-air missiles.
I don't have enough of a physics background to be confident in my quick numbers, so my question also involves someone being kind enough to check my math.
However, my real question is this: Is such a defense feasible and can it be scaled to satisfy the needs of a single soldier, a battalion in open terrain, and a spacefaring vessel? What impact would such a field have on people and things in or near it?
As mentioned here, employing magnetism in the extreme can have undesired effects, such as levitation and cellular disassembly. So anyone using a magnetism-based shield would need to have some form of protection against their protection.
Since magnetism only repels/attracts things with the same/opposite charge, and most things have a neutral charge (just don't walk across a carpet), anything that needed to be deflected by the field would need to be appropriately charged. Is there a way to manipulate the charge of an arbitrary object at distance, such as by firing electrons at it? (Note: this seems difficult and infeasible.)
To sum up, since this seems to be a little haphazard:
- Is a magnetism-based deflector shield a possible construct?
- If it is possible, what scale is feasible: soldier, battalion, ship, fleet?
- What impact would such a shield have on people and things in and around it?
- What protection, if any, would be needed by the user to defend against negative effects of the shield?
- How could the effective charge of any arbitrary object be manipulated at a distance of about 30 feet (9.1 meters)?