Chromospheric oscillations in K-2v bright points

The 3 minute waves observed in K-2v emission from bright points in the quiet solar chromosphere are shown to be oscillations of the atmosphere at the cutoff period of acoustic waves, implying impulsive excitation. Other interpretations of the period are shown not to be viable since they fail the dual requirement of spatial intermittence, in which most of the supergranulation cell interior is inert over the course of an hour, and temporal intermittence, in which the active locations in the cell interior are active at most half the time. It is speculated that the episodic excitation of the K-2v oscillations is due to collisions of granules with magnetic elements of mixed polarity with a field strength of at least 0.5 kG.