As I understand, Nuclear Fusion occurs when the nuclear forces overcome the electrostatic forces that act repulsively. But, what are these electrostatic forces? Are there force-carrying particles just photons?

  • $\begingroup$ You don’t need to think about this in a quantum-field-theoretic way using force-carrying particles for either the nuclear force or the electrostatic force. Just think about them as classical forces, one attractive and one repulsive. What do you mean by “What are these electrostatic forces?” They’re just the usual electrostatic repulsion between charged particles, in this case protons. $\endgroup$ – G. Smith Dec 17 '19 at 18:31