The fluctuation in brightness (‘twinkling’) of a radio source due to the scattering of radio waves by irregularities in interstellar matter (ISM). Much of the fluctuation is caused by the relative motion of the Earth and the source rather than of the ISM, and occurs on a time-scale of minutes to hours. Measurements of scintillation rate can be used to determine the velocities of pulsars across the line of sight. Interstellar scintillation of pulsar signals is closely related to pulse broadening.
Subjects: Astronomy and Astrophysics.