SUPERSONIC DOWNFLOWS IN A SUNSPOT LIGHT BRIDGE

Journal Article · Sat Oct 10 04:00:00 EDT 2009 · Astrophysical Journal (Online)

DOI:https://doi.org/10.1088/0004-637X/704/1/L29· OSTI ID:21367425

Louis, Rohan E; Mathew, Shibu K; Venkatakrishnan, P ^[1]

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1. Udaipur Solar Observatory, Physical Research Laboratory, Dewali, Badi Road, Udaipur, Rajasthan-313004 (India)

We report the discovery of supersonic downflows in a sunspot light bridge using measurements taken with the spectropolarimeter onboard the Hinode satellite. The downflows occur in small patches close to regions where the vector magnetic field changes orientation rapidly, and are associated with anomalous circular polarization profiles. An inversion of the observed Stokes spectra reveals velocities of up to 10 km s{sup -1}, making them the strongest photospheric flows ever measured in light bridges. Some (but not all) of the downflowing patches are cospatial and cotemporal with brightness enhancements in chromospheric Ca II H filtergrams. We suggest that these flows are due to magnetic reconnection in the upper photosphere/lower chromosphere, although other mechanisms cannot be ruled out.

• OSTI ID: 21367425
• Journal Information: Astrophysical Journal (Online), Journal Name: Astrophysical Journal (Online) Journal Issue: 1 Vol. 704; ISSN 1538-4357
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ATMOSPHERES
BRIGHTNESS
MAGNETIC FIELDS
MAGNETIC RECONNECTION
MAIN SEQUENCE STARS
OPTICAL PROPERTIES
PHOTOSPHERE
PHYSICAL PROPERTIES
POLARIZATION
SATELLITES
SOLAR ACTIVITY
SOLAR ATMOSPHERE
SPECTRA
STARS
STARSPOTS
STELLAR ACTIVITY
STELLAR ATMOSPHERES
SUN
SUNSPOTS