Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2025-01-02T11:02:46.340Z Has data issue: false hasContentIssue false
  • English
  • Français

Magnetic Diffusion in Star Formation

Published online by Cambridge University Press:  27 April 2011

Shantanu Basu  and
Wolf B. Dapp
Shantanu Basu
Affiliation:
Department of Physics and Astronomy, The University of Western Ontario, London, Ontario N6A 3K7, Canada email: [email protected]; [email protected]
Wolf B. Dapp
Affiliation:
Department of Physics and Astronomy, The University of Western Ontario, London, Ontario N6A 3K7, Canada email: [email protected]; [email protected]
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Magnetic diffusion plays a vital role in star formation. We trace its influence from interstellar cloud scales down to star-disk scales. On both scales, we find that magnetic diffusion can be significantly enhanced by the buildup of strong gradients in magnetic field structure. Large scale nonlinear flows can create compressed cloud layers within which ambipolar diffusion occurs rapidly. However, in the flux-freezing limit that may be applicable to photoionized molecular cloud envelopes, supersonic motions can persist for long times if driven by an externally generated magnetic field that corresponds to a subcritical mass-to-flux ratio. In the case of protostellar accretion, rapid magnetic diffusion (through Ohmic dissipation with additional support from ambipolar diffusion) near the protostar causes dramatic magnetic flux loss. By doing so, it also allows the formation of a centrifugal disk, thereby avoiding the magnetic braking catastrophe.

Keywords

MHDturbulencewavesstars: formationISM: cloudsISM: magnetic fields
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 6 , Symposium S270: Computational Star Formation , May 2010 , pp. 123 - 127
Copyright
Copyright © International Astronomical Union 2011

References

Allen, A., Li, Z.-Y., & Shu, F. H. 2003, ApJ, 599, 363CrossRefGoogle Scholar
Basu, S., Ciolek, G. E., Dapp, W. B., & Wurster, J. 2009, New Astron., 14, 483CrossRefGoogle Scholar
Basu, S. & Dapp, W. B. 2010, ApJ, 716, 427CrossRefGoogle Scholar
Basu, S. & Mouschovias, T. Ch. 1994, ApJ, 432, 720CrossRefGoogle Scholar
Basu, S., & Mouschovias, T. Ch. 1995, ApJ, 452, 386CrossRefGoogle Scholar
Contopoulos, I., Ciolek, G. E., & Königl, A. 1998, ApJ, 504, 247CrossRefGoogle Scholar
Crutcher, R. M. 2004, ApSS, 292, 225Google Scholar
Dapp, W. B. & Basu, S. 2010, A&A, 521, L56Google Scholar
Galli, D., Cai, M., Lizano, S., & Shu, F. H. 2009, RMxAC, 36, 143Google Scholar
Goodman, A. A., Benson, P. J., Fuller, G. A., & Myers, P. C. 1993, ApJ, 406, 528CrossRefGoogle Scholar
Heiles, C. & Troland, T. H. 2005, ApJ, 624, 773CrossRefGoogle Scholar
Krasnopolsky, R., Li, Z.-Y., & Shang, H. 2010, ApJ, 716, 1541CrossRefGoogle Scholar
Kudoh, T. & Basu, S. 2008, ApJ, 679, L97CrossRefGoogle Scholar
Kunz, M. W. & Mouschovias, T. Ch. 2010, 408, 322CrossRefGoogle Scholar
Li, Z.-Y. & McKee, C. F. 1996, ApJ, 464, 373CrossRefGoogle Scholar
Li, Z.-Y. & Nakamura, F. 2004, ApJ, 609, L83CrossRefGoogle Scholar
Machida, M. N., Inutsuka, S.-i., & Matsumoto, T. 2007, ApJ, 670, 1198CrossRefGoogle Scholar
Mestel, L. 1999, Stellar Magnetism (Oxford: Oxford Univ. Press)Google Scholar
Nakano, T., Nishi, R., & Umebayashi, T. 2002, ApJ, 573, 199CrossRefGoogle Scholar
Norman, M. L., Wilson, J. R., & Barton, R. T. 1980, ApJ, 239, 968CrossRefGoogle Scholar
Shu, F. H. 1977, ApJ, 214, 488CrossRefGoogle Scholar