Bibcode
Luna, M.; Karpen, J.; Díaz, A. J.; Knizhnik, Kalman; Muglach, Karin; Gilbert, Holly; Kucera, Therese
Referencia bibliográfica
Nature of Prominences and their role in Space Weather, Proceedings of the International Astronomical Union, IAU Symposium, Volume 300, pp. 155-158
Advertised on:
1
2014
Número de citas
1
Número de citas referidas
1
Descripción
Large-amplitude longitudinal (LAL) prominence oscillations consist of
periodic mass motions along a filament axis. The oscillations appear to
be triggered by an energetic event, such as a microflare, subflare, or
small C-class flare, close to one end of the filament. Observations
reveal speeds of several tens to 100 km/s, periods of order 1 hr,
damping times of a few periods, and displacements equal to a significant
fraction of the prominence length. We have developed a theoretical model
to explain the restoring force and the damping mechanism. Our model
demonstrates that the main restoring force is the projected gravity in
the flux tube dips where the threads oscillate. Although the period is
independent of the tube length and the constantly growing mass, the
motions are strongly damped by the steady accretion of mass onto the
threads. We conclude that the LAL movements represent a collective
oscillation of a large number of cool, dense threads moving along dipped
flux tubes, triggered by a nearby energetic event. Our model yields a
powerful seismological method for constraining the coronal magnetic
field strength and radius of curvature at the thread locations.