Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Temporal 1/f^\alpha Fluctuations from Fractal Magnetic Fields in Black
  Hole Accretion Flow   Rapid fluctuation with a frequency dependence of $1/f^{\alpha}$ (with $\alpha
\simeq 1 - 2$) is characteristic of radiation from black-hole objects. Its
origin remains poorly understood. We examine the three-dimensional
magnetohydrodynamical (MHD) simulation data, finding that a magnetized
accretion disk exhibits both $1/f^\alpha$ fluctuation (with $\alpha \simeq 2$)
and a fractal magnetic structure (with the fractal dimension of $D \sim 1.9$).
The fractal field configuration leads reconnection events with a variety of
released energy and of duration, thereby producing $1/f^\alpha$ fluctuations.

15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
1
The categories of this paper are: cs
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an