Magnetic field of a single charged particle

[yrjosmiel]

Let's say that there's nothing else in this universe except for 2 charged particles: q1 and q2.
q1 is moving relative to q2, moving at velocity v. I've read that a magnetic field is made by a moving charge. In this case, the moving charge q1 is moving relative to q2. What would the magnetic field made by q1 look like? Would it look circular, like the ones made by a current-carrying wire?

 

[Orodruin]

It would be circular, yes. Its strength would vary depending on distance and direction from the charge.

See for example http://academic.mu.edu/phys/matthysd/web004/l0220.htm

 

[yrjosmiel]

It would be circular, yes.

Is it circular just because it is or is there some other reason why?