1. Comparison of Magnetostatics and Electrostatics
Gauss’s law
no magnetic monopoles!
Ampere’s law
Boundary conditions:
far from all charges
far from all currents
Magnetic effects are attributable to electric charges in motion

2. Magnetic Vector Potential
The vector potential is not uniquely defined:
Both vector potentials produce the same magnetic field
One can require that
source field

3. Poisson’s equation
for line current
for surface current

4. Example: vector potential of a thin long straight wire
For
Example: find the vector potential of a uniform magnetic field
check using the Einstein notation