Although helioseismology may be somewhat unique in stimulating strong connections among researchers engaged in observation, theory, and modeling, the task group believes that the GONG and SOI experience illustrates the important point that scientists direct their research to interesting, well-posed problems involving opportunities to make a significant contribution.
The task group believes that the best scientific strategy for upgrading and constructing major observing facilities is represented by the following four projects, which are presented in order of priority.
Recommendation 1: Complete fabrication of the SOLIS facility over the next 3 years, operate it at an appropriate site, and provide funding for U.S. scientists for data analyses.
The Synoptic Optical Long-term Investigation of the Sun (SOLIS) instruments will make optical measurements of solar processes whose study requires sustained observations over periods of years. The program's overarching goal is to test and improve understanding of how and why stars like the Sun exhibit activity. Data from SOLIS will increase the scientific yield from solar spacecraft such as SOHO and TRACE and from ground-based projects such as GONG and RISE, and it is a key element of the proposed Solar Magnetism Initiative (see Appendix J).
When it becomes operational, the SOLIS instrument suite will enable the precision monitoring of daily solar activity with whole-disk vector magnetograms, velocitygrams, and spectroheliograms, replacing and greatly surpassing the capability offered by the Kitt Peak Vacuum Telescope and providing opportunities for new, heretofore infeasible, investigations of the Sun. Furthermore, if the facility's proposed state-of-the-art emission line coronagraph were funded, then SOLIS 's capabilities would surpass those of existing coronagraphs at Sac Peak as well as complement the High Altitude Observatory (HAO) white-light coronagraph, the Advanced Coronal Observing System (ACOS) that operates on Mauna Loa, Hawaii. A particular advantage of the proposed SOLIS emission line coronagraph would be its ability to correct accurately for sky brightness, thus providing greatly enhanced sensitivity.
The task group endorses the SOLIS project's timely start. SOLIS will be developed and built at Kitt Peak where a suitable building and observing platform are already available, but the SOLIS instruments will be portable, so that once SOLIS is brought into successful operation, it could be moved to a better observing site (perhaps to the superior site anticipated for the Advanced Solar Telescope—see below). With a planned 3-year development and construction schedule, SOLIS will come online near the peak activity (2000-2002) of the current solar cycle.