Ideal magnetohydrodynamic simulation of magnetic bubble expansion as a model for extragalactic radio lobes

Wei Liu, Scott C. Hsu, Hui Li, Shengtai Li, Alan G. Lynn

Research output: Contribution to journalArticle

7 Scopus citations

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.

Original languageEnglish (US)
Article number072905
JournalPhysics of Plasmas
Volume15
Issue number7
DOIs
StatePublished - Aug 15 2008

ASJC Scopus subject areas

  • Condensed Matter Physics

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