Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Long velocity tails in plasmas and gravitational systems   Long tails in the velocity distribution are observed in plasmas and
gravitational systems. Some experiments and observations in
far-from-equilibrium conditions show that these tails behave as 1/v^(5/2). We
show here that such heavy tails are due to a universal mechanism related to the
fluctuations of the total force field. Owing to the divergence in 1/r^2 of the
binary interaction force, these fluctuations can be very large and their
probability density exhibits a similar long tail. They induce large velocity
fluctuations leading to the 1/v^(5/2) tail. We extract the mechanism causing
these properties from the BBGKY hierarchy representation of Statistical
Mechanics. This leads to a modification of the Vlasov equation by an additional
term. The novel term involves a fractional power 3/4 of the Laplacian in
velocity space and a fractional iterated time integral. Solving the new kinetic
equation for a uniform system, we retrieve the observed 1/v^(5/2) tail for the
velocity distribution. These results are confirmed by molecular dynamics
simulations.

27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc