Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Generalized entropy production in collisionless plasma flows and
  turbulence   Collisionless plasmas exhibit nonthermal and anisotropic particle
distributions after being energized; as a consequence, they enter a low-entropy
state relative to the thermal state. The Vlasov equations predict that in a
collisionless plasma with closed boundaries, entropy is formally conserved,
along with an infinite set of other Casimir invariants; this provides a
seemingly strong constraint that may explain how plasmas maintain low entropy.
Nevertheless, entropy is commonly believed to be produced due to phase mixing
or nonlinear entropy cascades. The question of whether such anomalous entropy
production occurs, and of how to characterize it quantitatively, is a
fundamental problem in plasma physics. We construct a new theoretical framework
for characterizing entropy production (in a generalized sense) based on a set
of ideally conserved "Casimir momenta" derived from the Casimir invariants. The
growth of the Casimir momenta relative to the average particle momentum
indicates entropy production. We apply this framework to quantify entropy
production in particle-in-cell simulations of laminar flows and turbulent flows
driven in relativistic plasma, where efficient nonthermal particle acceleration
is enabled. We demonstrate that a large amount of anomalous entropy is produced
by turbulence despite nonthermal features. The Casimir momenta grow to cover a
range of energies in the nonthermal tail of the distribution, and we correlate
their growth with spatial structures. These results have implications for
reduced modeling of nonthermal particle acceleration and for diagnosing
irreversible dissipation in collisionless plasmas such as the solar wind and
Earth's magnetosphere.

20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat