A Comparison of the Morphology and Stability of Relativistic and Nonrelativistic Jets

摘要: We compare results from a relativistic and nonrelativistic set of two-dimensional axisymmetric jet simulations. For five simulations that either increase the Lorentz factor or decrease adiabatic index, we compute with equally useful power thrust. examine these for morphological dynamical differences, focusing on velocity field, width cocoon, age jets, internal structure itself. The primary result comparisons is field cannot be scaled up to give spatial distribution factors seen in Since local plays major role determining total intensity parsec-scale extragalactic this suggests simulation yield proper jet. Another general each its equivalents have similar ages (in time units, ≡R/aa, where R initial radius cylindrical aa sound speed ambient medium). Also, jets larger smaller cocoon size. In addition comparisons, completed four new investigate effect varying thermal pressure jets. confirm faster (larger factor) colder are more stable, amplitude longer wavelength variations. However, an exception occurs hottest which appear most stable. apparent stability does not follow linear normal mode analysis, there available growing Kelvin-Helmholtz modes. modes excited because lack perturbations able couple them. As example how can applied interpretation observations, use our estimate some parameters Cygnus A. Although none estimates alone determine if Cyg A nonrelativistic, density ratio values estimated by other means.