English

GONG Catalog of Solar Filament Oscillations Near Solar Maximum

Solar and Stellar Astrophysics 2018-06-13 v1

Abstract

We have catalogued 196 filament oscillations from the GONG HαH{\alpha} network data during several months near the maximum of solar cycle 24 (January - June 2014). Selected examples from the catalog are described in detail, along with our statistical analyses of all events. Oscillations were classified according to their velocity amplitude: 106 small-amplitude oscillations (SAOs), with velocities <10km  s1<10\mathrm{\, km \; s^{-1}}, and 90 large-amplitude oscillations (LAOs), with velocities >10km  s1>10\mathrm{\, km \; s^{-1}}. Both SAOs and LAOs are common, with one event of each class every two days on the visible side of the Sun. For nearly half of the events we identified their apparent trigger. The period distribution has a mean value of 58±\pm15 min for both types of oscillations. The distribution of the damping time per period peaks at τ/P=1.75\tau/P=1.75 and 1.251.25 for SAOs and LAOs respectively. We confirmed that LAO damping rates depend nonlinearly on the oscillation velocity. The angle between the direction of motion and the filament spine has a distribution centered at 2727^\circ for all filament types. This angle agrees with the observed direction of filament-channel magnetic fields, indicating that most of the catalogued events are longitudinal (i.e., undergo field-aligned motions). We applied seismology to determine the average radius of curvature in the magnetic dips, R89R\approx89 Mm, and the average minimum magnetic-field strength, B16B\approx16 G. The catalog is available to the community online, and is intended to be expanded to cover at least 1 solar cycle.

Keywords

Cite

@article{arxiv.1804.03743,
  title  = {GONG Catalog of Solar Filament Oscillations Near Solar Maximum},
  author = {Manuel Luna and Judith Karpen and José Luís Ballester and Karin Muglach and Jaume Terradas and Therese Kucera and Holly Gilbert},
  journal= {arXiv preprint arXiv:1804.03743},
  year   = {2018}
}

Comments

Accepted for publication in The Astrophysical Journal Supplement Series