Short-period auroral pulsations in λ6300 O I

λ6300 O I pulsations with quasi-periods of 2 to ∼20 seconds have been observed in pulsating auroras. The percentage modulation was only 0.03–0.9%, compared with modulations of up to 60% in λ5577 O.I and λ4278 N2+. It is shown that rapid quenching of the O¹D level allows a small part of the level population to follow the excitation function. The required quenching rates are derived, and these show that the shorter period pulsations occur lower in the atmosphere and so are associated with more energetic electrons. Pulsation heights can be deduced only if the quenching coefficients are known.