Optical Auroral Research

Diffuse aurora - structure, cause and magnetosphere-ionosphere interaction

Ingrid Sandahl (in memoriam 1949-2011), Urban Brändström (PI, project manager) and Timophey Sergienko (CoI).

Funded by the Swedish Research Council, for the period 2011-2013

Abstract

The diffuse aurora provides the largest part of the energy input to the ionosphere (70% or more) even during disturbed ionospheric conditions. In spite of this it has received much less attention from the scientific community than the other main auroral class, discrete aurora, and is not nearly as well understood. By measuring the detailed optical behaviour of diffuse aurora simultaneously on different spatial scales we will contribute to the understanding of its cause and effects, in particular its spatial and temporal structure. It is now known that the diffuse aurora can contain much fine structure, but it is not known if this is a general property. There is at present no good theoretical explanation for the fine structure. An attempt to develop a theory will be made in collaboration with the Polar Geophysical Institute in Apatity. The relationship between diffuse aurora and other auroral forms involving pitch angle scattering in the plasma sheet, such as pulsating aurora and certain types of black aurora, will also be investigated. We will use optical data from ALIS (Auroral Large Imaging System) at four wavelengths, an EMCCD imager, data from other ground-based instruments including EISCAT, and satellite data. Ionospheric modification experiments using the EISCAT heating facility will also be performed.

Further information

2011-2013: Diffuse aurora - structure, cause and magnetosphere-ionosphere interaction (full-text PDF 1MB, mostly in English, see appendix A for research programme).
The Auroral Large Imaging System (ALIS) Project website.
- Data (The ALIS online data archives)
- Publications database
Previous granted applications:
- 2005-2007: Fine structures of optical emissions from phenomena in the ionosphere investigated using 3D tomographic spectroradiometry (full-text PDF, 1MB).
- 2002-2004: Study of the fine-structure of the auroral ionosphere/thermosphere by 3D optical tomographic technique. (full-text PDF not available, further info in swedish)

Created: 2004-11-23/UB. Last change: urban*irf.se, 2013-02-12.