Emergence of twisted flux tubes in the solar atmosphere

Conference · Fri Jan 01 00:00:00 EST 1993 · American Astronomical Society, Bulletin; (United States)

OSTI ID:6176260

Matsumoto, R; Tajima, T; Shibata, K

Solar coronal loops observed in soft X-rays often show twisted structures. Sometimes, magnetic loops unwind after the topological change of magnetic field lines (McAllister et al. 1992). Since twisted flux tubes have more free energy than untwisted loop, when they emerge into the corona and interact with other loop or overlying magnetic fields, the release of magnetic energy will lead to energetic events such as flares, jets, and prominence eruptions. The authors performed a three-dimensional nonlinear MHD simulation of the evolution of twisted flux tubes. The initial state consists of hydrostatic atmosphere with a cold dense layer and a hot corona. In the cold layer, magnetic fields are concentrated in the horizontal flux tube. Fluid rotation at both ends of the flux tube is continuously applied. Such twisting motion generates torsional Alfven waves which propagate along the flux tube. After several rotations, the flux tube becomes kink unstable around the midpoint where the magnetic twists are accumulated. The flux tube is deformed into a super-coil structure. Later, twisted magnetic loops rise by the magnetic force and the buoyancy force created by sliding the gas along the flux tube. The length of each rising loop is about 10H in the cold layer, where H is the scale height. Further study will be conducted on the subsequent evolution of twisted flux tubes in the corona, and their interaction with overlying magnetic fields.

• OSTI ID: 6176260
• Report Number(s): CONF-9306217-; CODEN: AASBAR
• Journal Information: American Astronomical Society, Bulletin; (United States), Vol. 25:2; Conference: 182. meeting of the American Astronomical Society (AAS), Berkeley, CA (United States), 6-10 Jun 1993; ISSN 0002-7537
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
MAGNETIC FIELDS
SIMULATION
SOLAR CORONA
MAGNETIC FLUX
MAGNETOHYDRODYNAMICS
ALFVEN WAVES
ASTROPHYSICS
FREE ENERGY
NONLINEAR PROBLEMS
SCALE HEIGHT
SOFT X RADIATION
SOLAR ATMOSPHERE
TUBES
ATMOSPHERES
DIMENSIONS
ELECTROMAGNETIC RADIATION
ENERGY
FLUID MECHANICS
HEIGHT
HYDRODYNAMICS
HYDROMAGNETIC WAVES
IONIZING RADIATIONS
MECHANICS
PHYSICAL PROPERTIES
RADIATIONS
STELLAR ATMOSPHERES
STELLAR CORONAE
THERMODYNAMIC PROPERTIES
X RADIATION
661320* - Auroral
Ionospheric
& Magnetospheric Phenomena- (1992-)
665510 - Magnetohydrodynamics- (1992-)