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The Role of Magnetic Helicity in Structuring the Solar CoronaTwo of the most widely observed and striking features of the Suns magnetic field are coronal loops, which are smooth and laminar, and prominences or filaments, which are strongly sheared. Loops are puzzling because they show little evidence of tangling or braiding, at least on the quiet Sun, despite the chaotic nature of the solar surface convection. Prominences are mysterious because the origin of their underlying magnetic structure filament channels is poorly understood at best. These two types of features would seem to be quite unrelated and wholly distinct. We argue that, on the contrary, they are inextricably linked and result from a single process: the injection of magnetic helicity into the corona by photospheric motions and the subsequent evolution of this helicity by coronal reconnection. In this paper, we present numerical simulations of the response of a Parker (1972) corona to photospheric driving motions that have varying degrees of helicity preference. We obtain four main conclusions: (1) in agreement with the helicity condensation model of Antiochos (2013), the inverse cascade of helicity by magnetic reconnection in the corona results in the formation of filament channels localized about polarity inversion lines; (2) this same process removes most complex fine structure from the rest of the corona, resulting in smooth and laminar coronal loops; (3) the amount of remnant tangling in coronal loops is inversely dependent on the net helicity injected by the driving motions; and (4) the structure of the solar corona depends only on the helicity preference of the driving motions and not on their detailed time dependence. We discuss the implications of our results for high-resolution observations of the corona.
Document ID
20170005821
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Knizhnik, K. J.
(Johns Hopkins Univ. Baltimore, MD, United States)
Antiochos, S. K.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
DeVore, C. R.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
June 28, 2017
Publication Date
January 20, 2017
Publication Information
Publication: The Astrophysical Journal
Publisher: The American Astronomical Society
Volume: 835
Issue: 1
ISSN: 0004-637X
e-ISSN: 1538-4357
Subject Category
Solar Physics
Report/Patent Number
GSFC-E-DAA-TN42988
Distribution Limits
Public
Copyright
Other

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