SELF-ORGANIZED BRAIDING AND THE STRUCTURE OF CORONAL LOOPS

Journal Article · Sun Nov 01 00:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/705/1/347· OSTI ID:21389354

Berger, Mitchell A ^[1]; Asgari-Targhi, Mahboubeh ^[2]

---

1. Department of Mathematics, University of Exeter, Exeter EX4 4QF (United Kingdom)
2. Department of Mathematics, University College London, WC1E 6BT (United Kingdom)

The Parker model for heating of the solar corona involves reconnection of braided magnetic flux elements. Much of this braiding is thought to occur at as yet unresolved scales, for example, braiding of threads within an extreme-ultraviolet or X-ray loop. However, some braiding may be still visible at scales accessible to TRACE or Hinode. We suggest that attempts to estimate the amount of braiding at these scales must take into account the degree of coherence of the braid structure. In this paper, we examine the effect of reconnection on the structure of a braided magnetic field. We demonstrate that simple models of braided magnetic fields which balance the input of topological structure with reconnection evolve to a self-organized critical state. An initially random braid can become highly ordered, with coherence lengths obeying power-law distributions. The energy released during reconnection also obeys a power law. Our model gives more frequent (but smaller) energy releases nearer to the ends of a coronal loop.

• OSTI ID: 21389354
• Journal Information: Astrophysical Journal, Vol. 705, Issue 1; Other Information: DOI: 10.1088/0004-637X/705/1/347; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
COHERENCE LENGTH
EXTREME ULTRAVIOLET RADIATION
MAGNETIC FIELDS
MAGNETIC FLUX
MAGNETOHYDRODYNAMICS
RANDOMNESS
SOLAR CORONA
SUN
TOPOLOGY
ATMOSPHERES
DIMENSIONS
ELECTROMAGNETIC RADIATION
FLUID MECHANICS
HYDRODYNAMICS
LENGTH
MAIN SEQUENCE STARS
MATHEMATICS
MECHANICS
RADIATIONS
SOLAR ATMOSPHERE
STARS
STELLAR ATMOSPHERES
STELLAR CORONAE
ULTRAVIOLET RADIATION