How much energy would it take by accellerator to duplicate processes going on in a collapsing star?

Answer 1

The collision energies are easily attainable in particle accelerators. Google RHIC. They make quark-gluon plasmas every day with much higher energy density. There's a reason the we understand so much about the processes that go on in them.

Answer 2

Collision energies are not what is taking place in a collapsing star, it is compression caused by the gravity of the mass of the star, that's a lot of energy.