EFFECT OF INTERACTING RAREFACTION WAVES ON RELATIVISTICALLY HOT JETS

Journal Article · Fri Jun 01 04:00:00 EDT 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/751/2/140· OSTI ID:22037146

Matsumoto, Jin; Shibata, Kazunari ^[1]; Masada, Youhei ^[2]

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1. Kwasan and Hida Observatories, Kyoto University, Kyoto (Japan)
2. Graduate School of System Informatics, Department of Computational Science, Kobe University, Kobe (Japan)

The effect of rarefaction acceleration on the propagation dynamics and structure of relativistically hot jets is studied through relativistic hydrodynamic simulations. We emphasize the nonlinear interaction of rarefaction waves excited at the interface between a cylindrical jet and the surrounding medium. From simplified one-dimensional (1D) models with radial jet structure, we find that a decrease in the relativistic pressure due to the interacting rarefaction waves in the central zone of the jet transiently yields a more powerful boost of the bulk jet than that expected from single rarefaction acceleration. This leads to a cyclic in situ energy conversion between thermal and bulk kinetic energies, which induces radial oscillating motion of the jet. The oscillation timescale is characterized by the initial pressure ratio of the jet to the ambient medium and follows a simple scaling relation, {tau}{sub oscillation}{proportional_to}(P{sub jet,0}/P{sub amb,0}){sup 1/2}. Extended two-dimensional simulations confirm that this radial oscillating motion in the 1D system manifests as modulation of the structure of the jet in a more realistic situation where a relativistically hot jet propagates through an ambient medium. We find that when the ambient medium has a power-law pressure distribution, the size of the reconfinement region along the propagation direction of the jet in the modulation structure {lambda} evolves according to a self-similar relation {lambda}{proportional_to}t{sup {alpha}/2}, where {alpha} is the power-law index of the pressure distribution.

• OSTI ID: 22037146
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 751; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCELERATION
ASTRONOMY
ASTROPHYSICS
COMPUTERIZED SIMULATION
ENERGY CONVERSION
GALAXIES
HYDRODYNAMICS
INDEXES
JETS
KINETIC ENERGY
MODULATION
NONLINEAR PROBLEMS
ONE-DIMENSIONAL CALCULATIONS
OSCILLATIONS
RELATIVISTIC RANGE
SHOCK WAVES
TWO-DIMENSIONAL CALCULATIONS