Aims: High temporal and spatial resolution observations from the Rapid Oscillations in the Solar Atmosphere (ROSA) multiwavelength imager on the Dunn Solar Telescope are used to study the velocities of small-scale Hα jets in an emerging solar active region. Methods: The dataset comprises of simultaneous imaging in the Hα core, Ca II K, and G band, together with photospheric line-of-sight magnetograms. Time-distance techniques are employed to determine projected plane-of-sky velocities. Results: The Hα images are highly dynamic in nature, with estimated jet velocities as high as 45 km s−1. These jets are one-directional, with their origin seemingly linked to underlying Ca II K brightenings and G-band magnetic bright points. Conclusions: It is suggested that the siphon flow model of cool coronal loops is suitable for the interpretation of our observations. The jets are associated with small-scale explosive events, and may provide a mass outflow from the photosphere to the corona.
|Journal||Astronomy & Astrophysics|
|Early online date||30 Aug 2011|
|Publication status||E-pub ahead of print - 30 Aug 2011|