A study on the auroral tomography analysis

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Auroral tomography is an inverse problem to reconstruct 3-D luminous structure of aurora from multi-point CCD images. We had been studying auroral stereopsis by the functon fitting and algebraic MART methods before the first collaborative observations with ALIS optical observing network of the Swedish Institute of Space Physics came true and brought about 5-point monochromatic images in March, 1995. Tomographic inversion codes for 3-D reconstruction have since been developed, being upgraded from stereographic program, together with the computer user interface for manipulating multiple images. The algebraic techniques as the MART and SIRT were adapted with uniform field-aligned characteristic in its proximity assumed as a constraint to sometimes underdetermined auroral tomography. Analytic methods based on the Radon transform were also studied. In December 1995,6-point observation was carried out, and various types of aurora images obtained so far were analyzed by the modified MART and … More SIRT methods. Studies on the uniqueness of reconstruction.legitimacy of camera imaging models and sub-voxel sophistication were also worked out in parallel with the analysis. Reconstructed structure contributes to quantitative study in view of elementary formation process and dynamical behavior of auroras. Further numerical tests for various inversion algorithms were also continued. Fully remotely-controlled ALIS operation in early 1977 aimed at conjunctive studies of aurora with FAST satellite and EISCAT radar. Comprehensive analyzes of these data are still underway. Tomographic analysis has been undertaken with the result of further indications on the altitude profiles at different wavelength, stopping height distribution along aurora and structures of vortex or multiple arcs. Restoration of absolute value of auroral emission rate by the radiometric calibration of camera characteristics using an integration sphere and computer visualization of reconstructed results have also been investigated. Less