Dynamics of localized packets of spiral density waves in gaseous disks

Abstract

We study the linear dynamics of spiral density wave packets (localized both in physical and wavenumber planes) in gaseous disks by the shearing sheet approximation using nonmodal approach combined with numerical calculations. The dynamics is determined by the disk flow non-normality and is well comprehended not in the physical, but in the wavenumber plane. Consequently, we do not use the classical characteristics of spectral analysis – corotation, Lindblad resonance – for the comprehension.