Colloquium 8 March 2017, 4 p.m. - Space weather event prediction models at CmPA
Coronal Mass Ejections (CMEs) are large-scale solar eruptive events in which large amounts of plasma (up to 1013-1016 g) and magnetic field are expelled into interplanetary space at very high velocities (typ. 450 km/s, but up to 3000 km/s). When sampled in situ by a spacecraft in the interplanetary medium, they are termed Interplanetary CMEs (ICMEs). They are nowadays considered to be the major drivers of space weather and the associated geomagnetic activity, causing substantial economic damage. A report from the National Research Council of the National Academies in 2008 estimates that the advent of an event such as the one which occurred in September 1859 (called the Carrington event) would cost today between 1000 and 2000 billion dollars (!) and would take 4 to 10 years in repairs to recover, an order of magnitude more than that of Hurricane Katrina. The average occurrence of such severe events is estimated to once in 100 to 200 years. The ‘normal’ space weather events, however, accumulate to an estimated economic loss in Europe of 10 billion €/year. Therefore, the modeling of CME onset and their interplanetary propagation up to the impact on the Earth’s magnetosphere (affecting the ionosphere, thermosphere, radiation belts, etc.) is a key issue for more reliable space weather forecasts which are provided on a daily basis at regional warning centers, e.g. in Uccle (at the Royal Observatory of Belgium, ROB).
We will discuss 2.5D (axi-symmetric) magnetic flux rope models and 2.5D and 3D self-consistent magnetohydrodynamics (MHD) simulation models for the onset of CMEs under solar minimum conditions, and for their interaction with coronal streamers and subsequent evolution up to 1AU. Observations are used to constrain the models by providing initial and boundary conditions. These solar observations, as well as the resulting characteristic plasma parameters they produce at 1AU compared to (ACE) observations, provide excellent tools to validate the models. These advanced CME models have been integrated in the new physics-based forecasting-targeted inner heliosphere model Euhforia (‘European heliospheric forecasting information asset’), we are developing. We are in the process of validating the model by comparing with observational data of a selection of well-documented cases as well as with ENLIL results. The current state-of-the-art will be reviewed.
Fig: snapshot of a flux-rope CME evolutions simulation showing the magnetic field lines and the radial velocity (color coded) in the equatorial plane and a meridional plane (from J. Pomoell).
4 p.m.: lecture
Prof. Stefaan Poedts,
Centre for mathematical Plasma-Astrophysics
Department of Mathematics - KU Leuven
Auditorium 00.225, Celestijnenlaan 200 A, 3001 Heverlee
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