[Physics] Magnetic field lines vs. Electric field lines

electric-fieldselectromagnetismmagnetic fieldsVector Fields

What's the difference between magnetic field and electric field lines?

Does $d\vec B$ point in the direction you would experience a force if you were a moving charged particle at that point? I know for a fact the electric field and electrostatic force are parallel, but since $F = q\ \vec v \times \vec B$ for magnetic forces. Does that actually mean though that if, say, in the following graphic:

enter image description here

Where the dot is a wire going in and out of the page, that the $d\vec B$ vectors are not showing how a moving charged particle will move in the field?

Basically, I feel justified in thinking electric field lines communicate how a test charge will move at any given point in space.

How can I juxtapose this with magnetic field lines>

Best Answer

If they existed, magnetic field lines point in the direction of the force experienced by a magnetic monopole (assuming only a B-field is present).

For electric monopoles (charges), if they are moving then the force they experience due to the magnetic field is always at right angles to the field lines. That is of course not a uniquely determined direction. The exact direction is determined by the particle charge and velocity, since the force must also be at right angles to the velocity.