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Subarcsecond Bright Points and Quasi-periodic Upflows Below a Quiescent Filament Observed by the IRIS
Using UV spectra and SJIs from the IRIS, and coronal images and magnetograms
from the Solar Dynamics Observatory (SDO), we present the new features in a
quiescent filament channel: subarcsecond bright points (BPs) and quasi-periodic
upflows. The BPs in the TR have a spatial scale of about 350580 km and
lifetime of more than several tens of minutes. They are located at stronger
magnetic structures in the filament channel, with magnetic flux of about
1010 Mx. Quasi-periodic brightenings and upflows are observed
in the BPs and the period is about 45 min. The BP and the associated
jet-like upflow comprise a "tadpole-shaped" structure. The upflows move along
bright filament threads and their directions are almost parallel to the spine
of the filament. The upflows initiated from the BPs with opposite polarity
magnetic fields have opposite directions. The velocity of the upflows in plane
of sky is about 550 km s. The emission line of Si IV 1402.77 {\AA} at
the locations of upflows exhibits obvious blueshifts of about 530 km
s, and the line profile is broadened with the width of more than 20 km
s. The BPs seem to be the bases of filament threads and the upflows are
able to convey mass for the dynamic balance of the filament. The
"counter-streaming" flows in previous observations may be caused by the
propagation of bi-directional upflows initiated from opposite polarity magnetic
fields. We suggest that quasi-periodic brightenings of BPs and quasi-periodic
upflows result from small-scale oscillatory magnetic reconnections, which are
modulated by solar p-mode waves.Comment: 6 pages, 6 figures, accepted in A&
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