“…Although early, single‐point observations indicated that shock acoustic waves excited by rocket launches can propagate as far as ~1500 km [ Donn et al , ], large‐area, long‐distance propagation of such waves has not previously been reported. Since a freely propagating acoustic wave would suffer from severe dissipation owing to kinematic viscosity, conductivity, and ion drag [ Drobzheva and Krasnov , ; Vadas and Nicolls , ], the waves' long‐distance propagation may result from ducting, which has been discussed extensively elsewhere [ Thome , ; Francis , ; Hunsucker , ; Ding et al , ; Matsumura et al , ].…”