Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ubiquitous torsional motions in type II spicules   Spicules are long, thin, highly dynamic features that jut out ubiquitously
from the solar limb. They dominate the interface between the chromosphere and
corona and may provide significant mass and energy to the corona. We use
high-quality observations with the Swedish 1-m Solar Telescope to establish
that so-called type II spicules are characterized by the simultaneous action of
three different types of motion: 1. field-aligned flows of order 50-100 km/s,
2. swaying motions of order 15-20 km/s, and 3. torsional motions of order 25-30
km/s. The first two modes have been studied in detail before, but not the
torsional motions. Our analysis of many near-limb and off-limb spectra and
narrow-band images yields strong evidence that most, if not all, type-II
spicules undergo large torsional modulation and that these motions, like
spicule swaying, represent Alfvenic waves propagating outward at several
hundred km/s. The combined action of the different motions explains the similar
morphology of spicule bushes in the outer red and blue wings of chromospheric
lines, and needs to be taken into account when interpreting Doppler motions to
derive estimates for field-aligned flows in spicules and determining the
Alfvenic wave energy in the solar atmosphere. Our results also suggest that
large torsional motion is an ingredient in the production of type-II spicules
and that spicules play an important role in the transport of helicity through
the solar atmosphere.

7
The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys