Fusion Reaction

A fusion reaction is a nuclear reaction in which light atomic nuclei combine to form a heavier nucleus, releasing energy in the process.

Definition

Nuclear fusion is the process by which two light atomic nuclei combine to form a single heavier nucleus. The mass of the resulting nucleus is slightly less than the sum of the original masses, with the difference converted to energy according to Einstein’s equation $E = mc^2$.

Primary Fusion Reactions

D-T Reaction (Deuterium-Tritium)

The most feasible reaction for fusion power:

$$\text{D} + \text{T} \rightarrow {}^4\text{He} (3.5 \text{ MeV}) + n (14.1 \text{ MeV})$$

D-D Reaction (Deuterium-Deuterium)

$$\text{D} + \text{D} \rightarrow {}^3\text{He} + n + 3.27 \text{ MeV}$$ $$\text{D} + \text{D} \rightarrow \text{T} + p + 4.03 \text{ MeV}$$

D-He3 Reaction

$$\text{D} + {}^3\text{He} \rightarrow {}^4\text{He} + p + 18.3 \text{ MeV}$$

Requirements

• Extremely high temperatures (100+ million degrees Celsius)
• Sufficient plasma density
• Adequate energy confinement time

These requirements are summarized by the Lawson criterion.

Related Terms

• Plasma - Where fusion reactions occur
• Confinement - Keeping conditions suitable for fusion
• Tokamak - A device for achieving fusion
• Stellarator - Another fusion device