A novel approach to probe the spatial structure of not-too-dense radiation track in condensed matter on the scale that, on the one hand, substantially exceeds the mean size of a single spur (<10 nm), and, on the other hand, is less than a characteristic size of the whole track, produced by a single electron of an energy of ~10 keV in an organic media (several microns), is suggested. Such an approach is based on the analysis of the joint effects of both external magnetic field, which allows obtaining information about intraspur recombination, and the external electric field, which increases the probability of the encounter of ions from neighbouring spurs, on the radiation-induced fluorescence from an irradiated medium. The computer simulation of ion recombination in model tracks, which are to represent the real track formed by a single quantum of energy of about 20 keV in liquid dodecane and squalane, has been performed. It has been demonstrated that within the first microsecond after irradiation the ion recombination process in the studied alkane solutions can be represented using a set of 25–30 spherical spurs, which contain 3–4 primary ion pairs and have radii of 3–4 nm. Within the frameworks of the model used, the closest fit has been obtained assuming that in the model track the neighbouring spurs are located successively in random directions with a characteristic distance between them as large as 45 nm.