Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Determining the Intrinsic CME Flux Rope Type Using Remote-sensing Solar
  Disk Observations   A key aim in space weather research is to be able to use remote-sensing
observations of the solar atmosphere to extend the lead time of predicting the
geoeffectiveness of a coronal mass ejection (CME). In order to achieve this,
the magnetic structure of the CME as it leaves the Sun must be known. In this
article we address this issue by developing a method to determine the intrinsic
flux rope type of a CME solely from solar disk observations. We use several
well known proxies for the magnetic helicity sign, the axis orientation, and
the axial magnetic field direction to predict the magnetic structure of the
interplanetary flux rope. We present two case studies: the 2 June 2011 and the
14 June 2012 CMEs. Both of these events erupted from an active region and,
despite having clear in situ counterparts, their eruption characteristics were
relatively complex. The first event was associated with an active region
filament that erupted in two stages, while for the other event the eruption
originated from a relatively high coronal altitude and the source region did
not feature the presence of a filament. Our magnetic helicity sign proxies
include the analysis of magnetic tongues, soft X-ray and/or EUV sigmoids,
coronal arcade skew, filament emission and absorption threads, and filament
rotation. Since the inclination of the post-eruption arcades was not clear, we
use the tilt of the polarity inversion line to determine the flux rope axis
orientation, and coronal dimmings to determine the flux rope footpoints and,
therefore, the direction of the axial magnetic field. The comparison of the
estimated intrinsic flux rope structure to in situ observations at the
Lagrangian point L1 indicated a good agreement with the predictions. Our
results highlight the flux rope type determination techniques that are
particularly useful for active region eruptions, where most geoeffective CMEs
originate.

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The categories of this paper are: alg-geom
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The categories of this paper are: ao-sci
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The categories of this paper are: gr-qc
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The categories of this paper are: physics
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The categories of this paper are: supr-con
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The categories of this paper are: adap-org
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The categories of this paper are: q-fin
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The categories of this paper are: eess
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The categories of this paper are: stat
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The categories of this paper are: q-bio
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: econ
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The categories of this paper are: math
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The categories of this paper are: q-alg
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The categories of this paper are: atom-ph