Magnetic Flux Transport by turbulent reconnection in astrophysical flows

Abstract

The role of MHD turbulence in astrophysical environments is still highly debated. An important question that permeates this debate is the transport of magnetic flux. This is particularly important, for instance, in the context of star formation. When clouds collapse gravitationally to form stars, there must be some magnetic flux transport. otherwise the new born stars would have magnetic fields several orders of magnitude larger than the observed ones. Also, the magnetic flux that is dragged in the late stages of the formation of a star can remove all the rotational support from the accretion disk that grows around the protostar. The efficiency of the mechanism which is often invoked to allow the transport of magnetic fields in the different stages of star formation, namely, the ambipolar diffusion, has been lately put in check. We here discuss an alternative mechanism for magnetic flux transport which is based on turbulent fast magnetic reconnection. We review recent results obtained from 3D MHD numerical simulations that indicate that this mechanism is very efficient for decoupling and transport magnetic flux from the inner denser regions to the outskirts of collapsing clouds in the different stages of star formation. We also discuss this mechanism in the context of dynamo processes and speculate that it can play a role both in the solar dynamo and in accretion disk dynamo processes.

10 pages, 2 figures, review submitted to Physica Scripta

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Cited by in corpus (9)

• Turbulent Reconnection and Its Implications
• On the role of tachoclines in solar and stellar dynamos
• Protostellar Accretion Flows Destabilized by Magnetic Flux Redistribution
• Disc formation in turbulent cloud cores: is magnetic flux loss necessary to stop the magnetic braking catastrophe or not?
• Magnetic Reconnection in Astrophysical Environments
• Theory and Applications of Non-Relativistic and Relativistic Turbulent Reconnection
• Inconsistency in the Standard Model for Thin Accretion Disks
• Counterexample of the magnetorotational instability in two-dimensional axial symmetry
• Turbulence and Dynamo Interlinks