Context. We study the upward propagation of a localizedvelocity pulse that is initially launched below the transition regionwithin the solar atmosphere. The pulse quickly steepens into a shock,which may lead to the formation of spicules. Aims. We aim to explore the spicule formation scenario in the framework of the rebound shock model. Methods. We solve two-dimensional time-dependentmagnetohydrodynamic equations numerically to find spatial and temporaldynamics of spicules. Results. The numerical simulations show that the strong initialpulse may lead to the quasi periodic rising of chromospheric materialinto the lower corona in the form of spicules. The periodicity resultsfrom the nonlinear wake that is formed behind the pulse in thestratified atmosphere. The superposition of rising and falling offplasma portions resembles the time sequence of single and double(sometimes even triple) spicules, which is consistent withobservational findings. Conclusions. The two-dimensional rebound shock model may explainthe observed speed, width, and heights of type I spicules, as well asobserved multi-structural and bi-directional flows. The model alsopredicts the appearance of spicules with 3-5min period due to theconsecutive shocks. Key words: magnetohydrodynamics (MHD) - instabilities - Sun: atmosphere
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