Bridging support for ROSA operations facility in the UK

Energy generated at the centre of the Sun by nuclear fusion flows out to the surface, and subsequently heats the various components of the atmosphere, including the photosphere, chromosphere and corona. This heating often leads to rapid changes in the intensities of spectral lines which are formed in different atmospheric regions. Observing and modelling such rapid changes, which often take place on very short timescales (less than 1 second) are hence vital to properly understand energy outflow in the Sun and how the atmosphere is heated. Unfortunately however, there are few instruments capable of observing the Sun at sufficiently high cadence to reliably detect rapid changes in the atmosphere. In particular, satellite-based instrumentation has not been able to observe the Sun at very high cadence due to telemetry restrictions.

However, in 2006 we obtained funding from both the STFC and our host institute, Queen's University Belfast (QUB), to construct a state-of-the-art imager - Rapid Oscillations in the Solar Atmosphere (ROSA) - capable of observing the Sun simultaneously in multiple wavebands at a cadence of up to 200 Hz. ROSA was successfully commissioned in 2008 on the Dunn Solar Telescope (DST) at the National Solar Observatory (NSO) Sacramento Peak in the USA. It was subsequently delivered as a common-user instrument and made available on the DST for an initial 3-year period from August 2009 - July 2012. As part of our agreement with the NSO, the UK received a guaranteed minimum of 20 days per year observing time on the DST during this 3-year period.

ROSA provides both unprecedented time resolution (5 milliseconds) and spatial resolution, as we have developed image reconstruction techniques that allow extremely sharp images of the Sun to be obtained with ROSA on the DST. Indeed, we can resolve structures smaller than 100 km in size on the solar surface, which lies at a distance of 150 million km from Earth. This is equivalent to resolving an object less than 1 cm across which is 15 km away. Additionally, the multiple wavebands of ROSA permit up to 7 regions of the solar atmosphere to be observed simultaneously. Hence effectively the whole atmosphere from the low photosphere to the upper chromosphere can be observed and analysed as one coupled system. In particular, ROSA allows the investigation of oscillatory and transitory phenomena at an unprecedented level of detail, either as a standalone instrument or in conjunction with STFC-supported satellite missions.

It was important for the UK solar physics community to benefit from the STFC investment in ROSA, and fully exploit the guaranteed time allocation on the DST. Modest STFC funding was hence awarded to establish a Support Facility for ROSA operations in the UK, based at QUB. This provides support for all activities associated with ROSA observing programmes by the UK community, including (i) proposal preparation, (ii) observing support at the DST, (iii) data reduction, including the application of image reconstruction, (iv) development and maintenance of a ROSA archive. It has proved to be very successful, with for example 54 days of observing time on the DST awarded to UK proposals since the start of 2010 alone. In addition, in the last 15 months a total of 8 papers on ROSA data have been published or are in press in major international journals, including 6 in Astrophysical Journal Letters, with another 3 under review and 4 in preparation.

Recently, we have renewed our agreement with the NSO to host ROSA for the further 3-year period August 2012 - July 2015. Once again, the agreement includes a provision of at least 20 days per year reserved for UK proposals, and hence we seek a renewal of our funding for the Support Facility. However, we only request funding from August 2012 - March 2014; support beyond this date will be requested in our Consolidated Grant proposal, due for submission in February 2013 with a start date of April 2014.

1. Public engagement

Astronomy is undoubtedly the most popular area of physics with schoolchildren and the general public. It can help to enthuse children about physics (and science in general), and encourage them to study the subject at school and university. Hence the societal impact of astronomy is very high indeed, in terms of the Public Understanding of Science (PUS). The Applicants are highly active in PUS programmes linked to their research. Our outreach programmes, which will continue over the grant period, include:

- Presentations and talks at the annual events: (i) QUB Horizons in Physics (400 4th- and 5th-form students), (ii) Physics Open Days (200 6th-form students), (iii) Physics Teachers Conference (100 Physics teachers from schools in Ireland).

- Presentations to schools, both at primary and secondary level, either in the classroom or at QUB. These include `Why is the Sky Blue?' (Mathioudakis) and `To Boldly Go Where No-one Has Gone Before' (Keenan). We also provide these presentations to amateur astronomical clubs and societies, as well as further education colleges.

- We host work experience days for schoolchildren, including 6-week projects during the summer, funded by the Nuffield Foundation. Our PDRAs and PhD students are also involved in outreach schemes, such as Researchers in Residence.

- A private benefactor has recently provided £100K to enhance our PUS activities, in particular to encourage students into STEM subjects.


2. Knowledge Exchange engagement

2.1 Detector development

The detectors in ROSA were developed by ANDOR Technology, who have identified large format, high-speed CCDs as a growing market, e.g. in biomedicine, experimental physics and astronomy. In collaboration with ANDOR and European groups (including MSSL), we obtained funding from the EU/FP7 Programme for a Design Study for the European Solar Telescope. QUB, ANDOR and MSSL led this study in the area of large format, low noise, high-speed CCDs. We are currently undertaking a similar study for detectors for a new US solar telescope. Our workplan includes: (i) custom design solutions for large area, low noise cameras operating at high frame rates; (ii) investigation of the design of mosaic platforms; (iii) addressing the issue of multi-port readout functionality. We are also considering grant applications in the area of detector development, including to InvestNI.

2.2 Fusion research

Tokamaks are plasma devices that have been built for the study and eventual generation of nuclear fusion. Research on tokamaks is a multi-billion dollar worldwide industry, due to the possibility of developing a commercial nuclear fusion energy source. There are several tokamaks at the Culham Centre for Fusion Energy, including JET, the world's largest. The Applicants have strong engagement with Culham (who fund a QUB PDRA to work at Culham), linked to our solar physics programmes, due to the similarities between tokamak plasmas and those found in the Sun. Currently, we are developing a spectroscopic diagnostic for the alpha-particle yield during fusion, of great importance to the fusion community.