The Principal Investigators (PIs) intend to take advantage of a unique opportunity for complete access to the Dutch Open Telescope (DOT) on La Palma in the Canary Islands, which specializes in high-resolution solar imaging. For this project, this science team is being offered the entire 2010 observing season which runs from April to October at La Palma. This effort is extremely timely, given the delayed rise of activity in solar cycle 24 that has followed the deepest solar minimum in over a century. The year 2010 provides the only opportunity in this decade for scientists to study the rise of a new solar cycle after such a deep minimum of activity.
The DOT is a superior facility for high-resolution ground-based solar imaging, taking advantage of advanced on-site optical speckle processing. The DOT exploits excellent daytime seeing conditions on La Palma which minimize turbulence and cloud obscuration. The DOT is also capable of tomographic observations of the Sun using filters set at nine wavelengths, with each optical wavelength sampling a different height in the solar atmosphere.
This international research effort will directly contribute to improved space weather forecasts of coronal mass ejections and solar flares. The lead PI is from a small woman-owned company and this effort will directly involve four female scientists, as well as one additional female scientist as an external collaborator. This project therefore will contribute to diversity and increased participation of under-represented groups in the physical sciences.
Nature of the Project This NSF Rapid Award grant was for acquiring extensive research quality data on solar filament channels, filaments and prominences at the Dutch Open Telescope (DOT). The DOT is a high resolution solar research telescope located near the peak of highest mountain, Roque de Los Muchachos on the island of La Palma in the Canary Islands. This site is renowned for intervals of stable atmospheric conditions known as "good seeing" and therefore excellent image quality. The project was a collaboration between scientists and engineers at the Dutch Open telescope and the international research team of scientists organized through Helio Research, the recipient of the Rapid Award. Figure 1 illustrates the topic of this data collection project and the value of international scientific collaborations in solar research. An image of a solar filament recorded at the DOT is shown in the upper left panel (a). Auxiliary images from the Solar Dynamics Observatory (SDO) in (b), and in (c) from one of the STEREO satellites, show different aspects of the same filament and its environment. The latter two U.S. research satellites programs mutually benefit from high quality ground-based solar telescope observations such as obtained during our project. Helio Research and the PROM team were eligible to propose for an NSF Rapid Award in relation to two grants to Helio Research from the NSF for (1) Collaborative Research: Testing a New Concept for the Long-term Build-up to Coronal Mass Ejections and (2) SHINE: How New Active Regions Trigger Erupting Filaments and Associated Coronal Mass Ejections (CMEs). The scientific objectives of the Rapid Award are the same as for the supporting research grants but for the Rapid Award there were also the practical goals of training observers, observing, organizing the data, preliminary reduction of the data, and making the data available for use by the research team and the broader solar research community. Outcomes of the Project The most important outcome was the successful acquisition of the proposed data base of research quality primarily on filament channels, filaments and prominences. In Figure 2, we show the range of filaments observed during the project. Panel (a) shows two adjacent very young active regions with a new narrow filament between them and another near the region border as indicated by arrows. When active regions decay, they develop taller and longer filaments but always in narrow zones between areas of positive and negative magnetic flux as seen by comparing panels (a) and (d) in Figure 1. The magnetic fields around filaments coincide with the bright areas in Figure 2 called "plage". More plage means higher magnetic flux density except under arch filament systems, such as shown in Figure 2, where the flux density is always high. Another very important aspect of filaments that we needed to record was their velocities in our line-of-sight. This was accomplished at the DOT with a tunable filter and is possible because of a physical phenomenon called the Doppler Effect. Due to the Doppler effect, mass moving toward observers on Earth is shifted to shorter wavelengths than the core position of the H alpha line. Mass moving away from the observer Earth is shifted to longer wavelengths. The shorter wavelength side of the Ha spectral line is called the "blue" wing while the longer is called the "red" wing. The appearance of blue-shfted and red-shifted mass in fine thread-like structure in a filament is illustrated in Figure 3. The Scientific Results from the Data Base The analyses of these data are being conducted and reported under the supporting grants. A few significant preliminary results already show the value of the data set: finding unique sites in filament channels where mass enters and exits the spine confirmation of the hypothesis that cancelling magnetic fields are closely associated with filament formation. confirming evidence of that cancelling magnetic fields at the ends of filament barbs are also associated with mass influx into filaments establishing that the normal counterstreaming velocities of mass in active region filaments can be higher than previously thought by at least a factor of 2 recording of an example of the rare type of prominence known as a "coronal cloud prominence" and confirming that this type of prominence forms only after a coronal mass ejection Access to the Data Base Plans are being made for the data acquired to be also available through a data-base organization called "The Virtual Solar Observatory". The available types of data consist of: 1. Summary listings of the 2010 data in Tables at dotdb.phys.uu.nl/wiki/data_storage_log 2. Quicklook movies via links in the last column in the dataTables (1) 3. Frame-selected data sets corresponding to the quicklook movies at the same DOT ftp site 4. Summary listings of the speckle reconstructed data sets of highest quality at dotdb.phys.uu.nl/wiki/despeckled
