event
Monday 14 Mar 2016: 3D electron density distributions in the solar corona during solar minima: assessment for more realistic solar wind modelling (GAFD Seminar)
Dr Judith de Patoul - University of Exeter
H103 14:30-16:00
The distribution of the magnetic field generated in the solar interior and connected into the solar wind influences most coronal phenomena including large-scale and slowly evolving coronal structures. Knowledge of the electron density distribution in the solar corona can serve as a tracer of the configuration of the coronal magnetic field and provide constraints on the field configurations for coronal modelling as well as on initial conditions for solar wind modelling. We work with polarized SOHO/LASCO-C2 images from the last two recent minima of solar activity (1996-1997 and 2008-2010), devoid of coronal mass ejections. We derive the 4D electron density distributions in the corona by applying a newly developed time-dependent tomographic reconstruction method. First, we compare the results with both a polytropic and thermodynamic MHD models. Second, we study the temporal variation with the solar cycle in the polar and equatorial regions during the two solar minima. Finally, we focus on the highest-density structures and measure their differential rotation well above the surface. Such valuable information on 4D electron density distributions and large-scale structures could help to connect the sources of the solar wind to their in-situ counterparts in future missions such as Solar Orbiter.
