LABORATORY EXPERIMENTS, NUMERICAL SIMULATIONS, AND ASTRONOMICAL OBSERVATIONS OF DEFLECTED SUPERSONIC JETS: APPLICATION TO HH 110

Abstract

Collimated supersonic flows in laboratory experiments behave in a similar\nmanner to astrophysical jets provided that radiation, viscosity, and thermal\nconductivity are unimportant in the laboratory jets, and that the experimental\nand astrophysical jets share similar dimensionless parameters such as the Mach\nnumber and the ratio of the density between the jet and the ambient medium.\nLaboratory jets can be studied for a variety of initial conditions, arbitrary\nviewing angles, and different times, attributes especially helpful for\ninterpreting astronomical images where the viewing angle and initial conditions\nare fixed and the time domain is limited. Experiments are also a powerful way\nto test numerical fluid codes in a parameter range where the codes must perform\nwell. In this paper we combine images from a series of laboratory experiments\nof deflected supersonic jets with numerical simulations and new spectral\nobservations of an astrophysical example, the young stellar jet HH 110. The\nexperiments provide key insights into how deflected jets evolve in 3-D,\nparticularly within working surfaces where multiple subsonic shells and\nfilaments form, and along the interface where shocked jet material penetrates\ninto and destroys the obstacle along its path. The experiments also underscore\nthe importance of the viewing angle in determining what an observer will see.\nThe simulations match the experiments so well that we can use the simulated\nvelocity maps to compare the dynamics in the experiment with those implied by\nthe astronomical spectra. The experiments support a model where the observed\nshock structures in HH 110 form as a result of a pulsed driving source rather\nthan from weak shocks that may arise in the supersonic shear layer between the\nMach disk and bow shock of the jet's working surface.\n