WP1: Solar activity and its influence on the heliosphere and geospace

The WP1-related research encompasses empirical and theoretical research on the solar activity (solar eruptive activity, coronal holes and corotating interaction regions, evolution of active regions, solar rotation and solar 11-year activity cycle, long-term changes of the solar activity, etc.) and its influence on the state of the heliosphere and geospace, including the space weather forecasting.

 

T1.1. Eruptive processes in the solar atmosphere and variability of the solar wind

In T1.1 the role of ideal and resistive MHD processes is investigated in detail. The kink and torus instability, as well as to the physical relationship between CMEs and flares is studied, which includes the role of magnetic reconnection and the effect of self-inductivity on the evolution of the CME electric-current system. Nonlinear processes included in the formation and propagation of MHD shock waves (global-coronal and interplanetary) are being studied from empirical and theoretical point of view, including numerical simulations. The analysis of kinematics and dynamics of coronal and heliospheric propagation of CMEs is also performed. The central issue of the research is modelling in the context of space weather forecasting. Besides the CME-propagation modelling, the effects of active regions and equatorial coronal holes on the state of the background solar wind and interplanetary magnetic field is also studied, paying special attention to the evolutionary aspects of these phenomena.

 

T1.2. Geoeffectiveness of solar activity and space weather

The geoeffectiveness of CMEs is investigated in detail, with special emphasis on the forecasting based on the remote spaceborne white-light coronagraphic and coronal EUV observations of the dynamics of coronal eruptions. Similar studies are also performed for the corotating interaction regions (CIRs) associated with equatorial coronal holes (CHs). It is expected that the results achieved in the scope of this task will provide a better understanding of the CME-ICME connection and their space-weather effects, particularly GMSs and FDs. Furthermore, the results should provide early-warning procedures and forecasting of the GMS and FD level. Finally, the procedures developed in T1.2 will be set on the HO web page for a public usage.

 

T1.3. Long-term changes of solar activity and solar rotation

In Task 1.3, characteristics and evolution of the solar 11-year activity cycles is studied, including possibilities for the forecasting of the activity level of forthcoming cycles. This aspect of the research is extended also to the phenomenon of the long-term modulations of the 11-year solar-activity cycle and to the research related to the so called "space-climate" studies. Consequently this objective is closely related to the research of the Earth-climate effects (see WP2). For the analysis of the long term variations of solar activity cosmogenic C-14 and Be-10 data are used as proxies.