What design purpose does a concussion mortar serve?

A concussion mortar is specifically designed to produce a loud sound without causing damage. This is its primary purpose, and it achieves this by using blank charges or minimal explosive material to generate a concussive noise rather than launching a projectile. This feature is valuable in special effects displays where auditory impact is desired for enhancing the audience's experience, such as in theatrical productions or concerts.

In contrast to the other choices, a concussion mortar is not primarily focused on scattering debris, launching aerial fireworks, or creating visual smoke trails. The scattering of debris generally pertains to different types of pyrotechnic devices that produce visual effects and may include projectiles. Aerial fireworks are typically launched using traditional mortars designed for that purpose. Similarly, visual smoke trails are created by different types of devices that produce smoke, not by concussion mortars, which are focused on sound effects.