The Second Flight of the Sunrise Balloon-borne Solar Observatory: Overview of Instrument Updates, the Flight, the Data, and First Results

Abstract

The Sunrise balloon-borne solar observatory, consisting of a 1 m aperture telescope that provided a stabilized image to a UV filter imager and an imaging vector polarimeter, carried out its second science flight in June 2013. It provided observations of parts of active regions at high spatial resolution, including the first high-resolution images in the Mg ii k line. The obtained data are of very high quality, with the best UV images reaching the diffraction limit of the telescope at 3000Å after Multi-Frame Blind Deconvolution reconstruction accounting for phase-diversity information. Here a brief update is given of the instruments and the data reduction techniques, which includes an inversion of the polarimetric data. Mainly those aspects that evolved compared with the first flight are described. A tabular overview of the observations is given. In addition, an example time series of a part of the emerging active region NOAA AR 11768 observed relatively close to disk centre is described and discussed in some detail. The observations cover the pores in the trailing polarity of the active region, as well as the polarity inversion line where flux emergence was ongoing and a small flare-like brightening occurred in the course of the time series. The pores are found to contain magnetic field strengths ranging up to 2500 G and, while large pores are clearly darker and cooler than the quiet Sun in all layers of the photosphere, the temperature and brightness of small pores approach or even exceed those of the quiet Sun in the upper photosphere.

A Cancellation Nanoflare Model for Solar Chromospheric and Coronal Heating. III. 3D Simulations and Atmospheric Response

“…We note further that similar energetic events at the feet of coronal loops could possibly create jet-like structures observed at these locations (Chitta et al 2017a,b). In addition, given the increasing evidence for the presence of unresolved minority polarities in the photosphere (e.g., Solanki et al 2017;Smitha et al 2017), such ejections resulting from flux cancellation can give rise to jet-like features found inside plages and strong network associated with the unresolved underlying minority polarities (Wang 2016;Wang et al 2019). We expect that other small-scale phenomena, such as spicules, could be associated with reconnection at lower atmospheric heights between converging cancelling polarities, and can potentially be associated with the cool outflows predicted from our model for different values of parameter space (e.g., Samanta et al 2019).…”

High-frequency oscillations in small chromospheric bright features observed with Atacama Large Millimetre/Submillimetre Array

“…Morton et al [19] reported evidence of the sausage mode in a magnetic pore with a clear anti-phase relation of the width of the magnetic structure (waveguide) and the intensity observed at 4170 Å by the Rapid Oscillations in the Solar Atmosphere (ROSA; [20]) instrument at Dunn Solar Telescope. Furthermore, Gafeira et al [21] reported the anti-phase behaviour in Slender Ca II H Fibrils observed at 3969 Å with the SuFI instrument onboard the SUNRISE balloon-borne solar observatory [22,23].…”

High-resolution wave dynamics in the lower solar atmosphere

“…Solar physics research is ideally positioned to make rapid discoveries over the coming decades, with the imminent full-scale operation of the 4 m DKIST facility, in addition to ongoing work linked to the development of the 2 m Indian National Large Solar Telescope (NLST; [51]) and the 4 m European Solar Telescope (EST; [52]). In addition to these ground-based observatories, next-generation balloon-based and space-borne facilities, including the continually updated SUNRISE observatory [53,54], Solar Orbiter [55] and the JAXA M-class Solar-C [56] future mission, will help probe the photospheric and chromospheric interactions with other regions of the solar atmosphere on unprecedented scales. In particular, novel instrumentation, including fibre-fed imaging spectrographs (e.g.…”