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Revisiting the ABC flow dynamo
The ABC flow is a prototype for fast dynamo action, essential to the origin
of magnetic field in large astrophysical objects. Probably the most studied
configuration is the classical 1:1:1 flow. We investigate its dynamo properties
varying the magnetic Reynolds number Rm. We identify two kinks in the growth
rate, which correspond respectively to an eigenvalue crossing and to an
eigenvalue coalescence. The dominant eigenvalue becomes purely real for a
finite value of the control parameter. Finally we show that even for Rm =
25000, the dominant eigenvalue has not yet reached an asymptotic behaviour. Its
still varies very significantly with the controlling parameter. Even at these
very large values of Rm the fast dynamo property of this flow cannot yet be
established
Flow-based reservation marking in MPLS networks
2007-2008 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe
Molecular Dynamics in a Grand Ensemble: Bergmann-Lebowitz model and Adaptive Resolution Simulation
This article deals with the molecular dynamics simulation of open systems
that can exchange energy and matter with a reservoir; the physics of the
reservoir and its interactions with the system are described by the model
introduced by Bergmann and Lebowitz.Despite its conceptual appeal, the model
did not gain popularity in the field of molecular simulation and, as a
consequence, did not play a role in the development of open system molecular
simulation techniques, even though it can provide the conceptual legitimation
of simulation techniques that mimic open systems. We shall demonstrate that the
model can serve as a tool to devise both numerical procedures and conceptual
definitions of physical quantities that cannot be defined in a straightforward
way by systems with a fixed number of molecules. In particular, we discuss the
utility of the Bergmann-Lebowitz (BL) model for the calculation of equilibrium
time correlation functions within the Grand Canonical Adaptive Resolution
method (GC-AdResS) and report numerical results for the case of liquid water.Comment: 31 pages, 6 figure
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