Ideal magnetohydrodynamic simulation of magnetic bubble expansion as a model for extragalactic radio lobes
Year: 2008
Type: article
Abstract: Nonlinear ideal magnetohydrodynamic (MHD) simulations of the propagation and expansion of a magnetic “bubble” plasma into a lower density, weakly magnetized background plasma, are presented. These simulations mimic the geometry and parameters of the Plasma Bubble Expansion Experiment (PBEX) [A. G. Lynn, Y. Zhang, S. C. Hsu, H. Li, W. Liu, M. Gilmore, and C. Watts, Bull. Am. Phys. Soc. 52, 53 (2007)], which is studying magnetic bubble expansion as a model for extragalactic radio lobes. The simulations predict several key features of the bubble evolution. First, the direction of bubble expansion depends on the ratio of the bubble toroidal to poloidal magnetic field, with a higher ratio leading to expansion predominantly in the direction of propagation and a lower ratio leading to expansion predominantly normal to the direction of propagation. Second, a MHD shock and a trailing slow-mode compressible MHD wavefront are formed ahead of the bubble as it propagates into the background plasma. Third, the bubble expansion and propagation develop asymmetries about its propagation axis due to reconnection facilitated by numerical resistivity and to inhomogeneous angular momentum transport mainly due to the background magnetic field. These results will help guide the initial experiments and diagnostic measurements on PBEX.
Source: Physics of Plasmas
DOI: 10.1063/1.2948347
Authors: Wei Liu, Scott C. Hsu, Hui Li, Shengtai Li, Alan G. Lynn
Institutions: Los Alamos National Laboratory, University of New Mexico
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2043337765