Scintillation

INSTRUMENTAL

Scintillation is a flash or sparkle of light
Example: Scintillations of diamond-hard light.

Else
It's a process or state of emitting flashes of light.
In physics it's a small flash visible or
Ultraviolet light emitted by fluorescence in a phosphor
When struck by a charged particle or high-energy proton.

Elaboration
Scintillation of radio waves impacts
the power and phase of the radio signal.
Scintillation is caused by small-scale (tens of meters to tens of KM)
structure in the ionospheric electron density along the signal path
and is the result of interference of