We have applied the results obtained from the spatial nonlinear evolution of K-H modes in a cylindrical radiative jet, in order to interpret the formation of emission knots in HH jets.
The main differences between K-H and the alternative IWSs mechanisms can be summarized as follows:
The K-H scenario has the basic advantage of producing morphologies directly from the hydrodynamics of the problem, works under very general conditions, and does not depend on a peculiar behavior of the source but only on the establishment of pressure balance conditions between the jet and its environment. The main problems with K-H are shock morphologies, that only in few cases appear bow-shock like, and spatial distances within the jet are better interpreted by values of M about one half of those derived by observations of jet velocities (but not of jet-to-ambient velocity jumps).
Finally, magnetic fields may have an important impact on the phenomenology of both K-H and IWS scenarios, and the 2-D axial symmetry assumed in the calculations neglects the evolution of higher modes. Radiative 3-D calculations for the nonlinear evolution of K-H instabilities are in progress.
© European Southern Observatory (ESO) 1998
Online publication: April 28, 1998