# Where do discontinuities in the electromagnetic field occur?

• I
cuallito
Obviously at point charges, but where along boundaries? Would they theoretically occur in superconductors since they can carry infinite current (J -> infinity)?

Gold Member
2022 Award
One example are jumps of the normal component of the electric field along conducting surfaces, carrying a surface charge density. The jump is ##E_{n1}-E_{n2}=\sigma/\epsilon_0##.

Superconductors must be treated differently. They cannot be described by simply making the resistance 0 (or the electric conductivity to ##\infty##). A nice effective theory is the London theory:

https://en.wikipedia.org/wiki/London_equations

PeroK