For the fast few months, I have been scratching my head for this problem which I have faced while studying fusion.
In a hydrogen fusion, two hydrogen (for instance ) fuse to form a helium nucleus. I have heard that the hydrogen nuclei have negative potential energy due to interactions between the electron and proton electrostatic field.
Doubt 1 --》 can anyone explain me that what are the ideal conditions for negative potential energy which results in mass defect (right?)
Continuing, the nuclei fuse to form a helium nucleus which hass less mass than its reactants. Also nucleons in a helium nucleus experience more nuclear force between each other. What accounts for the increase in the energy which has to have an energy origin? Also combining all and taking in $E=mc^² $, HOW can we explain that nuclear fusion releases energy?