773 research outputs found
Eden growth model for aggregation of charged particles
The stochastic Eden model of charged particles aggregation in two-dimensional
systems is presented. This model is governed by two parameters: screening
length of electrostatic interaction, , and short range attraction
energy, . Different patterns of finite and infinite aggregates are observed.
They are of following types of morphologies: linear or linear with bending,
warm-like, DBM (dense-branching morphology), DBM with nucleus, and compact
Eden-like. The transition between the different modes of growth is studied and
phase diagram of the growth structures is obtained in
co-ordinates. The detailed aggregate structure analysis, including analysis of
their fractal properties, is presented. The scheme of the internal
inhomogeneous structure of aggregates is proposed.Comment: Revtex, 9 pages with 12 postscript figure
Deterministic growth model of Laplacian charged particle aggregates
The results of the computer simulation of the aggregates growth of the
similarly charged particles in the framework of deterministic Laplacian growth
model on a square lattice are presented. Cluster growth is controlled by three
parameters , where - Laplacian growth parameter, -
energy of a particle sticking to a cluster, - the screening length of
electrostatic interactions. The phase diagram of cluster growth is built in the
co-ordinates . The zones of different cluster morphology are
selected: I-the zone of finite X-like structures,II-the zone of infinite
ramified structures, controlled by electrostatic interactions, III-the zone of
infinite structures with electrostatic interactions effectively switched off.
Simple electrostatic estimations of the locations of the zone boundaries are
presented. It is shown that in general case within the zone II the continuous
change of , controlled by parameters , takes place. In the
degeneration limit when the given model transforms into deterministic version
of the Eden model (at ), the crossover from linear to compact
structures is observed when passing through the boundary between the
zones I and II.Comment: REVTEX, 3 pages with 4 postscript figure
Alignment in Gamma-Hadron Families of Cosmic Rays
Alignment of main fluxes of energy in a target plane is found in families of
cosmic ray particles detected in deep lead X-ray chambers. The fraction of
events with alignment is unexpectedly large for families with high energy and
large number of hadrons. This can be considered as evidence for the existence
of coplanar scattering of secondary particles in interaction of particles with
superhigh energy, eV. Data analysis suggests that production of
most aligned groups occurs low above the chamber and is characterized by a
coplanar scattering and quasiscaling spectrum of secondaries in the
fragmentation region. The most elaborated hypothesis for explanation of
alignment is related to the quark-gluon string rupture. However, the problem of
theoretical interpretation of our results still remains open.Comment: 15 pages, 2 tables, 6 figures (not included), Stanford University
preprint SU-ITP-94-2
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