Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evolution of twist-shear and dip-shear during X-class flare of 13
  December 2006: Hinode observations   The non-potentiality (NP) of the solar magnetic fields is measured
traditionally in terms of magnetic shear angle i.e., the angle between observed
and potential field azimuth. Here, we introduce another measure of shear that
has not been studied earlier in solar active regions, i.e. the one that is
associated with the inclination angle of the magnetic field. This form of
shear, which we call as the "dip-shear", can be calculated by taking the
difference between the observed and potential field inclination. In this
Letter, we study the evolution of dip-shear as well as the conventional
twist-shear in a $\delta$-sunspot using high-resolution vector magnetograms
from {\it Hinode} space mission. We monitor these shears in a penumbral region
located close to flare site during 12 and 13 December 2006. It is found that:
(i) the penumbral area close to the flaring site shows high value of
twist-shear and dip-shear as compared to other parts of penumbra, (ii) after
the flare the value of dip-shear drops in this region while the twist-shear in
this region tends to increase after the flare, (iii) the dip-shear and
twist-shear are correlated such that pixels with large twist-shear also tend to
exhibit large dip-shear, and (iv) the correlation between the twist-shear and
dip-shear is tighter after the flare. The present study suggests that
monitoring twist-shear during the flare alone is not sufficient but we need to
monitor it together with dip-shear.

13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc
15
The categories of this paper are: nucl-ex
2
The categories of this paper are: math
21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
4
The categories of this paper are: cond-mat
3
The categories of this paper are: physics