In a fission nuclear reaction, a heavy nucleus breaks up into smaller nuclei whereas in another nuclear reaction two or more than two possibly nuclei are fused to form a heavy nucleus. This nuclear reaction is called?

1. Chemical Reaction
2. Nuclear reaction
3. Fission nuclear reaction
4. Fusion nuclear reaction

Nuclear Fusion: A Technical Overview

Nuclear fusion represents a nuclear process wherein two or more atomic nuclei undergo a combination to yield one or more distinct atomic nuclei and subatomic particles. This amalgamation is accompanied by a significant energetic exchange, governed by the principles of mass-energy equivalence.

The fundamental mechanism involves the overcoming of the Coulombic barrier, the electrostatic repulsion inherent between positively charged nuclei. This necessitates extreme kinetic energies, typically achievable through conditions of high temperature (thermonuclear fusion, on the order of 107 to 108 Kelvin) and high density, to facilitate a sufficient probability of quantum tunneling and subsequent strong nuclear force interaction.

The energetic yield of fusion reactions, particularly those involving lighter nuclides (e.g., deuterium-tritium fusion), stems from the disparity in nuclear binding energy per nucleon between the reactants and the heavier product nuclei. The mass deficit (Δm) resulting from the fusion process is directly converted into energy (E) according to Einstein’s equation, E=Δmc2.

Natural stellar nucleosynthesis, the process by which stars generate energy, is primarily driven by various fusion pathways, such as the proton-proton chain and the CNO cycle. Controlled terrestrial fusion research aims to harness this energy source for power generation, with ongoing efforts focused on plasma confinement (e.g., tokamaks, stellarators) and inertial confinement techniques to achieve the requisite conditions for sustained fusion reactions.