An annular combustion (22) chamber and a transient plasma system (42) in communication with the annular combustion chamber (22) to sustain a spinning detonation wave. This system (42) is also called as “nanosecond pulsed plasma” system and a pulse generator (48) operates to generate by energy but intense high voltage pulses to provide tansient plasma (p); increasing the reactivity of the chemical species of the popelllants. The propulsion relies on constant pressure combustion (CDWE).