•	Common-volume measurement of sporadic sodium layer, sporadic E layer, and auroral ionization allow unique framework for evaluating E region dynamics
	•	Tested theories of sporadic sodium formation, results support the metallic ion neutralization mechanism
	•	Reduction in sodium density found to be causally related to auroral ionization.
	Heinselman, C.J., J.P. Thayer, and B.J. Watkins, “A high-latitude observation of sporadic sodium and sporadic E layer formation,” Geophys. Res. Lett. Vol. 25 , No. 16 , p. 3059, 1998.
	Heinselman, C.J., "Auroral effects on the gas phase chemistry of meteoric sodium", J. Geophys. Res., 105, D10, pp. 12181–12192, 2000.