EVIDENCE FOR A TRANSITION REGION RESPONSE TO PENUMBRAL MICROJETS IN SUNSPOTS

ABSTRACT Penumbral microjets (PMJs) are short-lived, fine-structured, and bright jets that are generally observed in chromospheric imaging of the penumbra of sunspots. Here we investigate their potential transition region signature by combining observations with the Swedish 1-m Solar Telescope in th...

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Bibliographic Details
Published in:Astrophysical journal. Letters 2015-10, Vol.811 (2), p.1-6
Main Authors: Vissers, G. J. M., Rouppe van der Voort, L. H. M., Carlsson, M.
Format: Article
Language:English
Subjects:
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
CALCIUM
CHROMOSPHERE
HEATING
Imaging
INTERFACES
JETS
MAGNESIUM
Microjets
POTENTIALS
Signatures
SILICON
Space telescopes
SUN
Sun: activity
Sun: chromosphere
Sun: transition region
SUNSPOTS
TELESCOPES
ULTRAVIOLET RADIATION
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Summary:ABSTRACT Penumbral microjets (PMJs) are short-lived, fine-structured, and bright jets that are generally observed in chromospheric imaging of the penumbra of sunspots. Here we investigate their potential transition region signature by combining observations with the Swedish 1-m Solar Telescope in the Ca ii H and Ca ii 8542 lines with ultraviolet imaging and spectroscopy obtained with the Interface Region Imaging Spectrograph (IRIS), which includes the C ii 1334/1335 , Si iv 1394/1403 , and Mg ii h & k 2803/2796 lines. We find a clear corresponding signal in the IRIS Mg ii k, C ii, and Si iv slit-jaw images, typically offset spatially from the Ca ii signature in the direction along the jets: from base to top, the PMJs are predominantly visible in Ca ii, Mg ii k, and C ii/Si iv, suggesting progressive heating to transition region temperatures along the jet extent. Hence, these results support the suggestion from earlier studies that PMJs may heat to transition region temperatures.
ISSN:2041-8205
2041-8213
2041-8213
DOI:10.1088/2041-8205/811/2/L33