...snip... The B61 family of weapons can be configured with a wide variety of yields, including 0.3, 1.5, 5, 10, 45, 60, 60, 80, 170, and 340 kilotons.7
In recent years, many military strategists have advocated the deployment and use of very small tactical nuclear weapons against Third-World adversaries, especially in earth-penetrating roles.8 The two lowest yields of the B61 family lie well within this so-called "mininuke" range. The percent of blast energy converted into shock waves in the earth is extremely sensitive to the depth of the blast. Thus even a small increase in earth penetrating capability can greatly affect the military utility of a nuclear weapon to hold deeply buried and hardened targets at risk. Hardening of the B61 to allow very high altitude release, with consequent high velocity ground impact, apparently provides such an increase in capability...snip...