Observation of O + ( 4 P- 4 D 0 ) lines in electron aurora over Svalbard

• Main Authors: Ivchenko, N., Rees, M. H., Lanchester, B. S., Lummerzheim, D., Galand, M., Throp, K., Furniss, I.
• Other Authors: School of Physics and Astronomy Nottingham, University of Nottingham, UK (UON), Alfven Laboratory, KTH Royal Institute of Technology Stockholm (KTH ), Geophysical Institute, Center for Space Physics Boston (CSP), Boston University Boston (BU), Atmospheric Physics Laboratory UCL London, University College of London London (UCL)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2004
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Norway; Svalbard
• Online Access: https://hal.science/hal-00317574; https://hal.science/hal-00317574/document; https://hal.science/hal-00317574/file/angeo-22-2805-2004.pdf

International audience This work reports on observations of O + lines in aurora over Svalbard, Norway. The Spectrographic Imaging Facility measures auroral spectra in three wavelength intervals (H ? , N + 2 1N(0,2) and N + 2 1N(1,3)). The oxygen ion multiplet (4639-4696Å) is blended with the band. It is found that in electron aurora, the brightness of this multiplet, is on average, about 0.1 of the total brightness. A joint optical and incoherent scatter radar study of an electron aurora event shows that the ratio is enhanced when the ionisation in the upper E-layer (140-190km) is significant with respect to the E-layer peak below 130km. Rayed arcs were observed on one such occasion, whereas on other occasions the auroral intensity was below the threshold of the imager. A one-dimensional electron transport model is used to estimate the cross section for production of the multiplet in electron collisions, yielding 0.18x10 -18 cm 2 .