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Numerical Magnetohydrodynamic Studies of Turbulence and Star Formation
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- By D. S. Balsara, N.C.S.A., University of Illinois at Urbana-Champaign, Illinois, U.S.A., A. Pouquet, Observatoire de la Cote d'Azur, France, D. Ward Thompson, Royal Observatory, Blackford Hill, Edinburgh, U.K., R. M. Crutcher, N.C.S.A., University of Illinois at Urbana-Champaign, Illinois, U.S.A.
- Edited by Jose Franco, Universidad Nacional Autónoma de México, Alberto Carraminana, Instituto Nacional de Astrofisica, Optica y Electronica, Tonantzintla, Mexico
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- Book:
- Interstellar Turbulence
- Published online:
- 04 August 2010
- Print publication:
- 28 May 1999, pp 261-266
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- Chapter
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Summary
In this paper we examine two problems numerically. The first problem concerns the structure and evolution of MHD turbulence. Simulations are presented which show evidence of forming a turbulent cascade leading to a self-similar phase and eventually a decay phase. Several dynamical diagnostics of interest are tracked. Spectra for the kinetic and magnetic energies are presented. The second problem consists of the formation of pre-protostellar cores in a turbulent, magnetized molecular clouds. It is shown that the magnetic field strength correlates positively with the density in keeping with observations. It is also shown that the density and magnetic fields organize themselves into filamentary structures. Through the construction of simulated channel maps it is shown that accretion onto the cores takes place along the filaments. Thus a new dynamical process is reported for accretion onto cores. We have used the first author's RIEMANN code for astrophysical fluid dynamics for all these calculations.
Introduction
The conference for which this paper is being written has been instrumental in opening the eyes of astronomers to the need for understanding turbulent processes in astrophysics. While several astrophysical environments where turbulent processes could be important were identified by numerous contributors in this conference, the pulsar scintillation measurements and the study of lines in molecular clouds provide two environments where the need for magnetohydrodynamic (MHD) turbulence is observationally well-founded. Since the MHD equations are highly non-linear analytical approaches sometimes prove to be of limited utility.