it does not - at leat Merriam Webster online:Batman wrote:
Merriam Webster disagrees.
Beam:
Pulse:a ray or shaft of light
collection of nearly parallel rays (as X rays) or a stream of particles (as electrons)
A pulse doesn't need to be a beam.rhythmical beating, vibrating, or sounding
a transient variation of a quantity (as electric current or voltage) whose value is normally constant
an electromagnetic wave or modulation thereof of brief duration
a brief disturbance of pressure in a medium; especially : a sound wave or short train of sound waves
A brief electromagnetic wave would be a pulse.
But a continued electromagnetic wave, even if it would not be a beam, could have a pulse, if there are modulations of brief duration in it.
You don't even understand Merriam Webster.