Aurorally produced O+ discovered above 400 km altitude, identified via multispectral analysis.
Narrow columns of ionization from 100 to 300 km produced by these auroras are associated with the Alfvenic electron acceleration region.
Semeter, J., “Critical comparison of OII(732–733 nm), OI(630 nm), and N2(1PG) emissions in auroral rays,” Geophys. Res. Lett., 30(5), 1225, doi:10.1029/2002GL015828, 2003.
Semeter, J., J. Vogt, G. Haerendel, K. Lynch, R. Arnoldy, " Persistent quasiperiodic precipitation of suprathermal ambient electrons in decaying auroral arcs", J. Geophys. Res., Vol. 106, No. A7, pp. 12,863-12,873, 2001.