ELI5. Why do you need to use heavy hydrogen to start a fusion reaction?

Question

I am pretty sure the sun fuses just standard one proton hydrogen. So why do we need to use deuterium and tritium for our bombs?

In: Physics

Answer 1

>I am pretty sure the sun fuses just standard one proton hydrogen.

It in fact does not! the proton-proton chain reaction (also referred to as the p-p cycle) is how stars of similar mass to our own sun get their “start”. As a proto star, the first “thing” that starts to happen is the fusion of two protons to form a deuterium isotop, which releases a small positron and a neutrino, converting one of the protons to a neutron.

The deuterium formation process is a critical step in proto-star development.

Larger stars develop differently, largely because the intense gravitational force is strong enough to overcome the Coulomb barrier.