What is Nuclear Fusion

Nuclear fusion is a reaction in which light atomic nuclei combine to form a heavier nucleus. This process releases enormous amounts of energy. The energy source of the Sun and stars is precisely this fusion reaction.

Principles of Fusion Reactions

The most feasible fusion reaction is between deuterium (D) and tritium (T).

$$\text{D} + \text{T} \rightarrow \text{He} + n + 17.6 \text{ MeV}$$

This reaction produces a helium nucleus (alpha particle) and a neutron, releasing 17.6 MeV of energy.

Why Fusion Energy

Fusion energy offers several advantages:

1. Abundant fuel: Deuterium from seawater, lithium from Earth’s crust
2. High energy density: Millions of times greater than fossil fuels
3. No greenhouse gas emissions
4. Unlike fission, no risk of runaway reactions

Lawson Criterion

To sustain fusion reactions, the plasma must meet certain conditions known as the Lawson criterion.

$$n \cdot \tau_E \cdot T > 3 \times 10^{21} \text{ keV} \cdot \text{s} / \text{m}^3$$

Where $n$ is plasma density, $\tau_E$ is energy confinement time, and $T$ is ion temperature.