TRANSITION-REGION/CORONAL SIGNATURES AND MAGNETIC SETTING OF SUNSPOT PENUMBRAL JETS: HINODE (SOT/FG), Hi-C, AND SDO/AIA OBSERVATIONS

ABSTRACT Penumbral microjets (PJs) are transient narrow bright features in the chromosphere of sunspot penumbrae, first characterized by Katsukawa et al. using the Ca ii H-line filter on Hinode's Solar Optical Telescope (SOT). It was proposed that the PJs form as a result of reconnection betwee...

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Bibliographic Details
Published in:The Astrophysical journal 2016-01, Vol.816 (2), p.1-11
Main Authors: Tiwari, Sanjiv K., Moore, Ronald L., Winebarger, Amy R., Alpert, Shane E.
Format: Article
Language:English
Subjects:
ALFVEN WAVES
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
CHROMOSPHERE
Coronas
FILAMENTS
HEATING
JETS
LIFETIME
MAGNETIC FIELDS
PHOTOSPHERE
PLASMA
RESOLUTION
Signatures
SOLAR CORONA
Solar observatories
SUN
Sun: chromosphere
Sun: corona
Sun: magnetic fields
Sun: photosphere
Sun: transition region
SUNSPOTS
TELESCOPES
TRANSIENTS
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Summary:ABSTRACT Penumbral microjets (PJs) are transient narrow bright features in the chromosphere of sunspot penumbrae, first characterized by Katsukawa et al. using the Ca ii H-line filter on Hinode's Solar Optical Telescope (SOT). It was proposed that the PJs form as a result of reconnection between two magnetic components of penumbrae (spines and interspines), and that they could contribute to the transition region (TR) and coronal heating above sunspot penumbrae. We propose a modified picture of formation of PJs based on recent results on the internal structure of sunspot penumbral filaments. Using data of a sunspot from Hinode/SOT, High Resolution Coronal Imager, and different passbands of the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory, we examine whether PJs have signatures in the TR and corona. We find hardly any discernible signature of normal PJs in any AIA passbands, except for a few of them showing up in the 1600 images. However, we discovered exceptionally stronger jets with similar lifetimes but bigger sizes (up to 600 km wide) occurring repeatedly in a few locations in the penumbra, where evidence of patches of opposite-polarity fields in the tails of some penumbral filaments is seen in Stokes-V images. These tail PJs do display signatures in the TR. Whether they have any coronal-temperature plasma is unclear. We infer that none of the PJs, including the tail PJs, directly heat the corona in active regions significantly, but any penumbral jet might drive some coronal heating indirectly via the generation of Alfvén waves and/or braiding of the coronal field.
ISSN:0004-637X
1538-4357
DOI:10.3847/0004-637X/816/2/92