Turbulent flow properties such as vortex formation and shedding are observed in thin sheets within solar prominences (with Hinode) and are described to occur quasi-periodically every few minutes due to thermal and magnetic buoyancy (e.g. Berger et al. 2008, 2010). Bubble-cavities are seen to form below prominences with a possible repetitive pattern over several hours, but the durations of these observations have not allowed confirmation so far. Also related to the thermodynamics and the global stability of prominences are ultra-long period (ULP) oscillations (8-30 hours) detected in EUV filaments (Foullon et al. 2004). Their period increase can be linked to a local ascent of the supporting magnetic field arcade and an increased probability of eruption (Foullon et al. 2009). Any such changes related or leading to prominence eruptions are essential for the evolution of the global corona and space weather.
1) What are the links between the different dynamics (e.g. low-frequency modulations of high-frequency waves)? Can we confirm a repetitive pattern in the bubble-cavities forming below prominences? If so, is this pattern related to the ULP oscillations observed in filaments on the disk?
2) Prominences offer a rich collection of possible instabilities and turbulent regimes (Ryutova et al. 2010). Is there a particular instability that causes the prominence to erupt? Can any of these instabilities coexist, combine or couple?
To answer these questions, we seek coordinated observations from Hinode with STEREO/SECCHI/EUVI and SDO/AIA in order to observe simultaneously the bubble-cavities of prominences on the limb with the EUV observations of filaments on the disk. STEREO/SECCHI/EUVI instruments will provide regular 171 and 195 absorption images, as well as He II 304 images of the filaments. SDO/AIA telescopes provide additional high-cadence context in the EUV, in particular with 171, 193, 304 and 211.
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