SeaLeg - Interesting question. About half physics, the other half, philosophical. For a moment, lets assume that Albert Einstein was probably smarter than both of us. His immediate response might be that the speed of light (or your particle) was at a maximum velocity. Therefore your question about creating a magnetic field around this particle, inferring that it was a symmetrical space, and had a leading and lagging displacement, or position, would invoke the problem that the leading component would have to have achieved a velocity greater than the speed of light to establish it's position in front of the particle. I think Einstein may have asked "where was the particle when you attempted to introduce the magnetic field, and why do you think the field would be created in front of the position of the particle at that instant"? Perhaps you would answer that half of the field would lag, or be behind the position or the particle, inferring that the other half would by necessity be leading, or ahead of the particle. To which, he may answer that the field would always be behind the particle, and never see the particle as the center of activity. I'm certainly not very sure of this, and invite other 'Experts' to share their theories. As I said, more of a philosophical question than a physical question. Looking forward to the input of others.