Nuclear fusion

Nuclear fusion is a physical process where two light Atomic nuclei collide and merge into a heavier nucleus, releasing tremendous energy. It powers the stars, including our Sun, and remains humanity's most promising clean energy frontier.

When nuclei fuse—typically hydrogen isotopes like deuterium and tritium—the resulting nucleus has slightly less mass than its precursors. That missing mass converts to energy via E=mc², an extraordinarily efficient transformation. The reaction requires extreme temperatures and pressures to overcome the nuclei's mutual electrical repulsion, a barrier called the Coulomb barrier.

Nature accomplishes fusion effortlessly in stellar cores. Scientists have replicated it in laboratories since the 1950s, most famously in thermonuclear weapons, but sustained, controlled fusion for electricity generation remains elusive. Major projects like ITER and the recent National Ignition Facility breakthrough demonstrate progress toward commercial fusion power.

The appeal is immense: fusion fuel is abundant (seawater contains enough deuterium for millennia), produces no greenhouse gases, and generates no long-lived radioactive waste. Yet engineering challenges—containing plasma hotter than the Sun's core, achieving net energy gain—have delayed practical fusion reactors for decades. The field pulses with renewed optimism and investment.

Related

Big Bang nucleosynthesis, Plasma (physics), Stellar nucleosynthesis, Tokamak, Renewable energy