engleski

The Drag-based Model

The Drag-Based Model (or just DBM) is a model used to calculate heliospheric propagation of interplanetary coronal mass ejections (ICMEs). The DBM is founded on the assumption that on large heliospheric distances, beyond 20 solar radii, Lorentz and gravity force cease and only the drag between solar wind and CME is dominant. The assumption relies on the facts that CME slower than solar wind accelerate and faster decelerate. In that collisionless environment resistivity and viscosity are low therefore the momentum and energy have to be transferred by MHD waves or similar phenomena. The final step is made in which the restriction of self-similar expansion is removed. That lead us to the possible integration of the DBM to any numerical model which provides background dataset for solar-wind speed. On the other hand, the DBM could be used in automatic real-time forecasting of CME kinematics and prediction of the impact parameters. For a given observed dataset, the DBM kinematic curve could be fitted by changing DBM parameters in order to find the minimum of quadratic deviation. Obviously, the prediction becomes better as the observational dataset expands. Finally, the DBM is useful because it is simple, fast and versatile. Its accuracy is not worse in comparison to the other advanced models (Vršnak et al., 2014) and therefore suited for a fast real-time space-weather forecasting (Žic et al., 2015).

plasma ; solar physics ; space weather ; numerical models

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