Why does two parallel currents attract each other when two proton beams repel each other?
[Physics] Two wires carrying current in same direction attract each other. But two proton beams repel each other. Why
electric-currentelectromagnetismforcesmagnetic fields
Best Answer
The wires carring a current are effectively electrically neutral (equal numbers of positive and negative charges) so the dominant force between the moving charges in the magnetic field produced by the other charge is the attractive Lorentz force.
When you have just beams of protons they are also subjected to the electrostatic repulsive force which is much stronger than the attractive Lorentz force and so there is net repulsive force between them.