COUPLED ALFVEN AND KINK OSCILLATIONS IN CORONAL LOOPS

Journal Article · Wed Mar 10 00:00:00 EST 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/711/2/990· OSTI ID:21394330

Pascoe, D J; Wright, A N

Observations have revealed ubiquitous transverse velocity perturbation waves propagating in the solar corona. However, there is ongoing discussion regarding their interpretation as kink or Alfven waves. To investigate the nature of transverse waves propagating in the solar corona and their potential for use as a coronal diagnostic in MHD seismology, we perform three-dimensional numerical simulations of footpoint-driven transverse waves propagating in a low beta plasma. We consider the cases of both a uniform medium and one with loop-like density structure and perform a parametric study for our structuring parameters. When density structuring is present, resonant absorption in inhomogeneous layers leads to the coupling of the kink mode to the Alfven mode. The decay of the propagating kink wave as energy is transferred to the local Alfven mode is in good agreement with a modified interpretation of the analysis of Ruderman and Roberts for standing kink modes. Numerical simulations support the most general interpretation of the observed loop oscillations as a coupling of the kink and Alfven modes. This coupling may account for the observed predominance of outward wave power in longer coronal loops since the observed damping length is comparable to our estimate based on an assumption of resonant absorption as the damping mechanism.

• OSTI ID: 21394330
• Journal Information: Astrophysical Journal, Vol. 711, Issue 2; Other Information: DOI: 10.1088/0004-637X/711/2/990; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABSORPTION
ALFVEN WAVES
COMPUTERIZED SIMULATION
MAGNETOHYDRODYNAMICS
OSCILLATIONS
PARAMETRIC ANALYSIS
PERTURBATION THEORY
SEISMOLOGY
SOLAR CORONA
SUN
TOPOLOGY
ATMOSPHERES
FLUID MECHANICS
HYDRODYNAMICS
HYDROMAGNETIC WAVES
MAIN SEQUENCE STARS
MATHEMATICS
MECHANICS
SIMULATION
SOLAR ATMOSPHERE
SORPTION
STARS
STELLAR ATMOSPHERES
STELLAR CORONAE