lowmegaton

Lowmegaton is an informal term used in discussions of nuclear weapons to describe explosive yields in the lower part of the megaton scale. It is not an official designation and does not have a standardized numerical definition across sources.

Definition and scope: In most academic and policy contexts, lowmegaton roughly refers to yields below one megaton, with common reference ranges around 0.01 to 0.3 megatons. Some writers extend the upper bound toward 0.5–1.0 Mt depending on context. Because it is informal, the exact boundary varies by author.

Measurement and effects: Yields are expressed in megatons of TNT-equivalent. One megaton equals about 4.184 petajoules. Effects such as blast overpressure, thermal radiation, and radiation exposure scale with yield and altitude and with the device’s design. In practical terms, a lowmegaton device would produce substantial but geographically constrained damage compared to larger megaton-range weapons.

Usage and significance: The term appears in policy debates, historical analysis, and risk assessments to distinguish large-scale strategic weapons from higher-yield or battlefield devices. It is commonly used to compare potential damages, deterrence implications, and treaty considerations without implying a formal standard.

Limitations: Because it is informal, "lowmegaton" lacks precision and is not suitable for technical specifications or official inventories. Researchers typically specify the exact yield rather than relying on the label.