Small-scale Hα jets in the solar chromosphere
Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Belfast, BT7 1NN, Northern Ireland, UK
2 Department of Physics and Astronomy, California State University, Northridge, CA 91330, USA
3 Air Force Research Laboratory, Solar and Solar Disturbances, Sunspot, NM 88349, USA
Received: 7 June 2011
Accepted: 3 August 2011
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 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 interpreting our observations. The jets are associated with small-scale explosive events, and may provide a mass outflow from the photosphere to the corona.
Key words: Sun: activity / Sun: chromosphere / Sun: faculae, plages / Sun: photosphere / Sun: surface magnetism
© ESO, 2011