The poster size limits are A0 portrait and A1 landscape.
New Light (from HMI) on Loop Prominence Systems
Dr Hugh Hudson (UC Berkeley and U of Glasgow)
Flare loops appear in the solar corona under a variety of descriptions, with systematic observations ranging from radio to X-ray wavelengths. We now add a new one (visible light) provided by the HMI instrument on SDO. Although not a coronagraph, this small optical telescope, part of the Solar Dynamics Observatory, clearly sees such structures and also provides full polarization information. From the latter (Stokes Q) we estimate the scattering mass of SOL2013-05-13T16 directly. Historically the observation of loop prominence systems in H-alpha and soft X-rays inspired the development of our current standard model of flare processes in the corona. This presentation describes the physics of the HMI observations in the context of observations at other wavelengths, and anticipates what they may tell us about the phenomenon of coronal rain.
A spectroscopic study of solar tornadoes
Mr Peter Levens (University of Glasgow)
Solar tornadoes are a phenomenon that is relatively little studied. They appear as rotating structures in certain Extreme Ultraviolet (EUV) wavelengths in images from the Atmospheric Imaging Assembly (AIA) aboard the SDO satellite, as well as in some studies by the Extreme-UV Imaging Spectrometer (EIS) on board Hinode. Here, using spectroscopic techniques on data from EIS in different EUV wavelengths, we investigate the nature of these events at different plasma temperatures. By looking at doppler shifts and intensity maps we can infer some information about the motion and structure of the tornadoes above the limb. Combining doppler results from both rastered images and sit-and-stare images we can see there is a clear red-blue split down the axis of the tornado. Along with the apparent longevity of this split doppler structure, we can say with some confidence that the structure is indeed rotating. However, there is much more to be investigated so that we can more fully understand these occurrences.
Effect of gravitational stratification on the propagation of a CME
Dr Paolo Pagano (University of St Andrews)
According to the flux rope ejection model, a magnetic flux rope is ejected from the solar corona and reaches the interplanetary space where it interacts with the pre-existing magnetic fields and plasma. The life span of a flux rope undergoes two main phases: the formation that occurs slowly and through equilibrium states, and the highly dynamic and fast ejection. In order to tackle the modelling challenges posed by these different time-scales, we couple two different models: the GNLFFF model of Mackay and van Ballegooijen, appropriate for the flux rope formation, and the MHD code AMRVAC, suitable to follow the flux rope ejection and the subsequent CME. This modelling technique allows us to describe the ejection of flux rope occurring in realistic magnetic coronal configuration. In the discussion, we will address the role of gravitational stratification on the development of the ejection and on the speed and shape of the CME. Moreover we will present more complex MHD simulation where also thermal conduction and radiative losses are considered and how these simulations would look like when observed by AIA on board of SDO and METIS, the new coronograph on board of Solar Orbiter.
Onset of the Kelvin-Helmholtz instability in quiescent prominences: role of partial ionisation
Dr Roberto Soler (University of the Balearic Islands (Spain))
High-resolution observations of quiescent prominences often show the presence of vortex flows and turbulent dynamics. From the theoretical point of view, some of these phenomena have been linked to plasma instabilities as, e.g., the Kelvin-Helmholtz Instability (KHI). The classical criterion for the onset of the KHI in fully ionised plasmas is that the shear flow velocity must be higher than the plasma Alfven velocity. This requires relatively large flow velocities that are not observed in actual prominences. Hence, the KHI should not be present in prominences according to the classical criterion. However, the simplification of full ionisation does not realistically represent the prominence plasma and the role of partial ionisation may be important. Here, we investigate the impact of partial ionisation on the onset of the KHI. We find that ion-neutral collisions cause the KHI to be triggered for shear flow velocities lower than the Alfven velocity. The required flow velocities are compatible with those observed in quiescent prominences.
The formation and evolution of solar prominences
Miss Stephanie Yardley (MSSL (UCL))
This study focuses on the role of the magnetic field in the formation and evolution of a solar prominence present in the quiet sun. In particular, to understand and quantify photospheric flux cancellation as the driver of prominence formation using H-alpha observations and line-of-sight magnetograms. Together with these techniques and the use of multi-wavelength plasma diagnostics, we hope to clarify and explain certain aspects of current theoretical models.
Statistical and 2D-spatial analysis of prominence oscillations
Dr Maciej Zapiór (University of the Balearic Islands)
We analyzed Doppler velocity oscillations in several prominences observed by various telescopes, namely: HINODE satellite in H-alpha spectral line, Sac Peak VTT in H-beta and Bialkow MSDP in H-alpha, based on series of Dopplergrams. Huge amount of data allowed us to perform investigations of prominence oscillations in a statistical way. We studied 2D spatial distribution and coherence of particular periods over prominences' bodies also.