For 10 points, name this vector quantity symbolized A, the curl of which is the magnetic field.
This entity is analogous to the 2-space potential flow stream function; in both cases, the associated fields are solenoidal. In cgs units, this quantity is given by the relativistic beta at the retarded time times its energy-like companion field, according to the LiÃ©nard-Wiechert potential equations. In the non-relativistic case in cgs units, this field is the integral over all space of the current density divided by the distance to the field point. The space-like part of the four-potential, this quantity is unique only up to the gradient of a gauge function. For 10 points, name this vector quantity symbolized A, the curl of which is the magnetic field.
This entity is analogous to the 2-space potential flow stream function; in both cases, the associated fields are solenoidal.
magnetic vector potential [or magnetic potential; prompt on A]