Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Solar differential rotation and properties of magnetic clouds   The most geoeffective solar drivers are magnetic clouds - a subclass of
coronal mass ejections (CME's) distinguished by the smooth rotation of the
magnetic field inside the structure. The portion of CME's that are magnetic
clouds is maximum at sunspot minimum and mimimum at sunspot maximum. This
portion is determined by the amount of helicity carried away by CME's which in
turn depends on the amount of helicity transferred from the solar interior to
the surface, and on the surface differential rotation. The latter can increase
or reduce, or even reverse the twist of emerging magnetic flux tubes, thus
increasing or reducing the helicity in the corona, or leading to the violation
of the hemispheric helicity rule, respectively. We investigate the CME's
associated with the major geomagnetic storms in the last solar cycle whose
solar sources have been identified, and find that in 10 out of 12 cases of
violation of the hemispheric helicity rule or of highly geoeffective CME's with
no magnetic field rotation, they originate from regions with "anti-solar" type
of surface differential rotation.

11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
16
The categories of this paper are: stat