Chromospheric Cloud-Model Inversion Techniques

Spectral inversion techniques based on the cloud model are extremely useful for the study of properties and dynamics of various chromospheric cloud-like structures. Several inversion techniques are reviewed based on simple (constant source function) and more elaborated cloud models, as well as on grids of synthetic line profiles produced for a wide range of physical parameters by different NLTE codes. Several examples are shown of how such techniques can be used in different chromospheric lines, for the study of structures of the quiet chromosphere, such as mottles/spicules, as well as for active region structures such as fibrils, arch filament systems (AFS), filaments and flares.