Three-dimensional reconstruction of the auroral arc emission from stereoscopic optical observations

The mathematics of emission computed tomography is applied to the three-dimensional reconstruction of the optical emission within an auroral arc. According to general experimental conditions, a very limited angular range and a small number of observers require an iterative back projection method. Parameters for the quantitative correspondence between the original and reconstructed volumes and between the images are defined and using this method, a theoretical arc can be reconstructed with root- mean-square errors of the images of less than 2%. The reconstruction accuracy of the volume can be improved with an increasing number of observers to root-mean-square errors of about 15%. Different geometries are tested but the best results are obtained as long as one observer looks along the magnetic field line through the auroral arc. The calculations confirm the range of suitable observation geometries to within 20 km from the field line through one of the observers.