Study of the Jovian Decameter Narrow- and Wideband Emission: Fine Time–Frequency Structures and Temporal Evolution

We present a study of fine time–frequency structures and their complex temporal evolution in the narrowband (NB) and wideband (WB) components of Jupiter’s sporadic decametric (DAM) emission, including cases where both components appear simultaneously in dynamic spectra. High-resolution observations of a Jovian radio storm on 26 November 2009, featuring emission from Io-C and Io-A″ sources, were recorded with the UTR-2 telescope (8–32 MHz) using a baseband digital receiver, enabling waveform acquisition suitable for offline multi-scale analysis. Spectral images were produced with a custom multi-scale algorithm incorporating high-pass filtering to suppress narrowband radio frequency interference (RFI) while preserving intrinsic Jovian signals. Windowed Fourier transforms traced the formation, temporal evolution, and internal structure of NB events and their relation to classical S- and L-bursts. Some NB events exhibit complex patterns requiring interpretations beyond standard classifications. Combined with spacecraft observations from Juno and the forthcoming JUICE mission, these data allow disentangling intrinsic emission physics from propagation effects. In particular, the analysis demonstrates the potential to study emissions arriving simultaneously from two spatially separated sources with different polarization. Future studies, combining high-resolution spectra from UTR-2, GURT, LOFAR, NenuFAR, NDA, LWA, and other instruments with spacecraft measurements, will further enable identification and characterization of modulation patterns in Jupiter’s DAM waves. These results provide constraints for DAM generation models, emphasize the value of polarization-resolved, high-resolution studies, and support the identification of emission sources and plasma media along the propagation path.