Normal07.8 磅02falsefalsefalseEN-USZH-CNX-NONEMicrosoftInternetExplorer4Transient events in the terrestrial and planetary magnetospheres

Gábor FacskóNormal07.8 磅02falsefalsefalseEN-USZH-CNX-NONEMicrosoftInternetExplorer4

时间：2013-10-30星期三下午 15: 00

Time：October30, 2013，Wensday, pm15: 00

地点：四楼报告厅

Normal07.8 磅02falsefalsefalseEN-USZH-CNX-NONEMicrosoftInternetExplorer4Preliminary analysis of one year long space climate simulation

Gábor Facskó

时间：2013-11-4星期一下午 15: 00

Time：November 4, 2013，Monday, pm15: 00

地点：四楼报告厅

Transient events in the terrestrial and planetary magnetospheres

Normal07.8 磅02falsefalsefalseEN-USZH-CNX-NONEMicrosoftInternetExplorer4In the foreshock and the magnetosheath plenty of different temporal (so-called transient) events lasting for several minutes could be observed: hot flow anomalies (HFA), foreshock bubbles (FBs), foreshock cavities, Larmor-size foreshock cavities, foreshock cavitons and short large amplitude magnetic signatures (SLAMS); furthermore super-magnetosonic subsolar magnetosheath jets downstream to the bow shock.The role of the energized particle measured by RAPID onboard Cluster was studied. It was proved that a higher (~600 km/s) solar wind velocity is a favorable condition for HFA formation. A large statistical study was provided based on 124 events identified in Cluster measurements. The presence of turbulence with simultaneous wave activity was observed in the HFA cavity. The ruins of a HFA were observed in the distance tail by STEREO. The classical theory of HFA formation was ruined by observation of HFA formation with quasi-parallel and quasi-perpendicular regions on both sides of the discontinuity. Recently HFA formation without the presence of a tangential discontinuity and foreshock cavity transformation to HFA were discovered using THEMIS measurements.

The HFAs and SLAMS were also discovered at Mars, Saturn, Venus and Mercury. Their significance was underestimated, aside from being well known that the HFAs create a large bulge on the magnetopause and thus distort the magnetosheath. The supermagnetosonic magnetosheath jets impacted to the magnetosphere distort it. It was recently discovered that a HFA can cause increased aurora and PC5 wave activity. The number of these transient events was underestimated as well as their significance. During quiet and unperturbed solar wind conditions, these features can excite the magnetosphere and they have global influence.

Preliminary analysis of one year long space climate simulation

Normal07.8 磅02falsefalsefalseEN-USZH-CNX-NONEMicrosoftInternetExplorer4A wide range of so-called synthetic global MHD runs was provided using the Grand Unified Magnetosphere Ionosphere Coupling simulation (GUMICS) investigating the extent of solar wind drivers that can influence magnetospheric dynamics. The solar wind density, velocity and the interplanetary magnetic field had different magnitudes and orientations; furthermore two F10.7 flux values were selected for solar radiation minimum and maximum values. The solar wind parameter values were constant such that a constant stable solution was archived. All configurations were run several times with three different (-15°, 0°, +15°) tilt angles in the GSE X-Z plane. As key parameters, the large-scale characteristics of the magnetosphere, including the magnetopause size and shape, geometry of the tail neutral sheet, magnetotail plasma pressure, tail lobe magnetic field, and cross-polar cap electric potential are used. The GUMICS-4 stationary solutions generally fit the statistical relations, however, with some discrepancies. Particularly, position of the subsolar magnetopause, neutral sheet shape and position, and the plasma sheet pressure during northward IMF agree well with statistical models. At the same time, the size of the tail magnetopause and the lobe magnetic field magnitude appear to be systematically lower compared to their empirical values. Furthermore, the ionospheric potential is smaller in magnitude compared to empirical relations.

Additionally a full year (155 Cluster orbits, from January 29, 2002 to February 2, 2003) is simulated using the Grand Unified Magnetosphere Ionosphere Coupling simulation (GUMICS) in the European Cluster Assimilation Technology project (ECLAT). This enables us to study the performance of a global magnetospheric model in an unprecedented scale both in terms of the amount of available observations and the length of the time series that can be compared. The solar wind for the simulated period, obtained from OMNIWeb, is used as input to GUMICS. We present an overview of various comparisons of GUMICS results to observations for the simulated year. Results along the Cluster reference spacecraft orbit to are compared to Cluster measurements. The Cross Polar Cap Potential (CPCP) results are compared to SuperDARN measurements. The IMAGE electrojet indicators (IU, IL) calculated from the ionospheric currents of GUMICS are compared to observations. Finally, Geomagnetically Induced Currents (GIC) calculated from GUMICS results along the Finnish mineral gas pipeline at Mätsälä are also compared to measurements.

Gábor Facskó

Normal07.8 磅02falsefalsefalseEN-USZH-CNX-NONEMicrosoftInternetExplorer4Gabor Facsko was born in Baja, Hungary and studied Theoretical Physics, Astronomy and Computer Science at the Eotvos Lorand University, Budapest. He started working in the KFKI Research Institute for Particle and Nuclear Physics (today: Wigner Research Centre for Physics), Budapest as Research Assistant and later Research Fellow. He graduated at the Eotvos Lorand University, Budapest in 2008. His thesis was written from the topic of hot flow anomalies (HFA) and small scale fluctuations of the interplanetary magnetic field (IMF) using Cluster magnetic field and energized particle measurements. In 2008 he moved to Orleans, France and worked in the Cluster WHISPER team at the Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E)/Centre National de Recherche Scientifique (CNRS). In 2010 he got a position in the Finnish Meteorological Institute, Helsinki, Finland. His recent research topic is global magnetohydrodynamic (MHD) plasma simulations and their verification. However he still continues research in his previous topics: the transient events, small scale IMF fluctuations, HFAs and developing data mining tools.