An optical study of multiple NEIAL events driven by low energy electron precipitation

Sullivan, J.M., Lockwood, M., Lanchester, B.S., Kontar, E.P. , Ivchenko, N., Dahlgren, H. and Whiter, D.K. (2008) An optical study of multiple NEIAL events driven by low energy electron precipitation. Annales Geophysicae, 26(8), pp. 2435-2447. (doi: 10.5194/angeo-26-2435-2008)

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Optical data are compared with EISCAT radar observations of multiple Naturally Enhanced Ion-Acoustic Line (NEIAL) events in the dayside cusp. This study uses narrow field of view cameras to observe small-scale, short-lived auroral features. Using multiple-wavelength optical observations, a direct link between NEIAL occurrences and low energy (about 100 eV) optical emissions is shown. This is consistent with the Langmuir wave decay interpretation of NEIALs being driven by streams of low-energy electrons. Modelling work connected with this study shows that, for the measured ionospheric conditions and precipitation characteristics, growth of unstable Langmuir (electron plasma) waves can occur, which decay into ion-acoustic wave modes. The link with low energy optical emissions shown here, will enable future studies of the shape, extent, lifetime, grouping and motions of NEIALs.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Kontar, Professor Eduard
Authors: Sullivan, J.M., Lockwood, M., Lanchester, B.S., Kontar, E.P., Ivchenko, N., Dahlgren, H., and Whiter, D.K.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Annales Geophysicae
Publisher:European Geosciences Union
Published Online:11 August 2008

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
398461Acceleration, propagation and emission of energetic particles from the sun to the earthEduard KontarParticle Physics & Astronomy Research Council (PPARC)PP/C001656/1Physics and Astronomy
465931Solar, stellar and cosmological plasmas: a synthesis of data, modelling and theory.Declan DiverScience & Technologies Facilities Council (STFC)ST/F002149/1Physics and Astronomy