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Possible enhancement of previously unobserved (NII) emissions in the mid‐day aurora associated with nightside substorm activity
Author(s) -
Myrabø H. K.,
Deehr C. S.,
Sivjee G. G.
Publication year - 1983
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl010i002p00172
Subject(s) - substorm , physics , spectral line , atmospheric sciences , cusp (singularity) , latitude , particle (ecology) , environmental science , low latitude , astrophysics , geophysics , ionosphere , magnetosphere , geology , astronomy , magnetic field , oceanography , geometry , mathematics , quantum mechanics
We report here the presence of previously unobserved NII emissions in several spectra of aurora from the dayside cusp region taken near Longyearbyen, Spitzbergen (74.3°N geomagnetic). The presence of the 3d³P° ‐ 4p³S transition giving rise to the triplet (6809, 6834, 6847A) is particularly obvious, but the spectra also show strong evidence of other NII emissions such as those from the 3d³D° ‐ 4p³D level. The forbidden [NII] (6548, 6584A) doublet seems also to be present, but less obvious than the NII (6809, 6834, 6847A) triplet. The presence or the enhanced level of these permitted emissions seems, on two occasions, to coincide with a sudden decrease in the characteristic energy of the local particle precipitation and with a high latitude substorm on the nightside. Integration time is so large (30 min) as to preclude a more exact correlation with the substorm. However, two otherwise identical situations occurred with no nightside substorm and neither increased NII emissions nor decreased particle energies were observed on the dayside.