|a 'back-burn' defense|
Preventative detonations of small nuclear devices sub-ground level, to create thick clouds to block the hot blast wave-front of an intruding nuclear detonation, coupled with preceding missile-deflection detonations, is especially convenient for island fortresses surrounded by deep water.
There is also some advantage in preventatively removing the atmosphere immediately before the intruding detonation, as although the device detonation still contains most of the energy, the atmospheric wall acts like a load-mismatch mirror-reflecting the assailant blast. A kind of nuclear back-burn.
Ultimately a sonic envelope may shield a city, building a steep-angled many-layered standing wave-front in the atmosphere around, and reflecting the blast to the sides.
A waffled-air-wall might also dissipate the leading-edge shockwave, by presenting a perforated velocity-distribution, medium, allowing incipient sharpness to dissipate.
This may significantly affect EMP, eg. Q-bomb/Q-cannon, where electrical conductivity or conduction velocity can be significantly altered [waffled]: Q-impact devices rely on E-M risetime sharpness of nanoseconds, measurable in feet, 1 nsec./ft, or meters, 3 nsec./m; however, such [air] frequencies are audible range, and disperse readily. (Ultrasonic frequencies applied from the side, can create long standingwave conductance varying "tubes", but cross conductivity is high, leaving even these low-efficient.)
A premise discovery under the title,