First direct optical observations of plasma flows using afterglow of O+ in discrete aurora
2009 (English)In: Journal of Atmospheric and Solar-Terrestrial Physics, ISSN 1364-6826, Vol. 71, no 2, 228-238 p.Article in journal (Refereed) Published
Imaging of active structured aurora in the forbidden O+ ion line at 732.0 nm provides a possibility of direct observation of plasma drifts in the topside ionosphere. The metastable O+ P-2 state has a radiative lifetime of 5 s, so the oxygen ions can be detected after the precipitation creating them has ceased. The decay time of the O+ emission is studied and modelled with a time-dependent electron transport and ion chemistry model. Four examples are given of O+ afterglow observed with the multi-spectral imager, auroral structure and kinetics (ASK), which was located near Tromso, Norway, in 2006. Estimates are given of drift velocities resulting from the analysis of the afterglow motions. Bulk plasma velocities of 340 and 720 m/s directed eastwards were found for two afterglowing arc filaments, corresponding to southward electric fields of 18 and 40 mV/m, respectively.
Place, publisher, year, edition, pages
2009. Vol. 71, no 2, 228-238 p.
Ionosphere, Plasma drift, Aurora, Oxygen ion, Electric fields, transition-probabilities, radar observations, rate coefficients, forbidden lines, electric-fields, ion drift, arcs, thermosphere, emission, airglow
Fusion, Plasma and Space Physics
IdentifiersURN: urn:nbn:se:kth:diva-18236DOI: 10.1016/j.jastp.2008.11.015ISI: 000264084600006ScopusID: 2-s2.0-59249108653OAI: oai:DiVA.org:kth-18236DiVA: diva2:336282
QC 20100525 Tidigare titel: First direct optical observations of plasma flows in the metastable 0+ ion in discrete aurora2010-08-052010-08-052010-12-17Bibliographically approved