Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Solar-cycle precursors and predictions   The sunspot number data during the past 400 years indicates that both the
profile and the amplitude of the solar cycle have large variations. Some
precursors of the solar cycle were identified aiming to predict the solar
cycle. The polar field and the geomagnetic index are two precursors which are
received the most attention. The geomagnetic variations during the solar minima
are potentially caused by the solar polar field by the connection of the solar
open flux. The robust prediction skill of the polar field indicates that the
memory of the dynamo process is less than 11 yrs within the framework of the
Babcock-Leighton flux transport dynamo. One possible reason to get the short
magnetic memory is the high magnetic diffusivity in the convective zone. Our
recent studies show that the radial downward pumping is another possible
reason. Based upon the mechanism, we well simulate the cycle irregularities
during RGO time period. This opens the possibility to set up a standard dynamo
based model to predict the solar cycle. In the end, the no correlation between
the polar field and the preceding cycle strength due to the nonlinearities and
random mechanisms involved in the sunspot emergences are stressed.

26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
19
The categories of this paper are: eess
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol