1,770 research outputs found
Thermo-kinetic approach of single-particles and clusters involving anomalous diffusion under viscoelastic response
We present a thermo-kinetic description of anomalous diffusion of
single-particles and clusters in a viscoelastic medium in terms of a
non-Markovian diffusion equation involving memory functions. The scaling
behaviour of these functions is analyzed by considering hydrodynamics and
cluster-size space random walk arguments. We explain experimental results on
diffusion of Brownian particles in the cytoskeleton, in cluster-cluster
aggregation and in a suspension of micelles.Comment: To be published in the Journal of Physical Chemistry
Generalized hydrodynamics of a dilute finite-sized particles suspension: Dynamic viscosity
We present a mesoscopic hydrodynamic description of the dynamics of colloidal
suspensions. We consider the system as a gas of Brownian particles suspended in
a Newtonian heat bath subjected to stationary non-equilibrium conditions
imposed by a velocity field. Using results already obtained in previous studies
in the field by means of a generalized Fokker-Planck equation, we obtain a set
of coupled differential equations for the local diffusion current and the
evolution of the total stress tensor. We find that the dynamic shear viscosity
of the system contains contributions arising from the finite size of the
particles.Comment: To appear in Physical Review
High frequency waves in the corona due to null points
This work aims to understand the behavior of non-linear waves in the vicinity
of a coronal null point. In previous works we have showed that high frequency
waves are generated in such magnetic configuration. This paper studies those
waves in detail in order to provide a plausible explanation of their
generation. We demonstrate that slow magneto-acoustic shock waves generated in
the chromosphere propagate through the null point and produce a train of
secondary shocks that escape along the field lines. A particular combination of
the shock wave speeds generates waves at a frequency of 80 mHz. We speculate
that this frequency may be sensitive to the atmospheric parameters in the
corona and therefore can be used to probe the structure of this solar layer
- …