Generation of Alfvén Waves by Small-Scale Magnetic Reconnection in Solar Spicules

Alfvén waves dissipation is an extensively studied mechanism for the coronal heating problem. These waves can be generated by magnetic reconnection and propagated along the reconnected field lines. Here, we study the generation of Alfvén waves at the presence of both steady flow and sheared magnetic field in the longitudinally density stratified of solar spicules. The initial flow is assumed to be directed along the spicule axis, and the equilibrium magnetic field is taken 1-dimensional and divergence-free. We solve linearized MHD equations numerically and find that the perturbed velocity and magnetic field oscillate similarly which can be interpreted as generation and propagation of Alfvénic waves along spicule axis. The results of calculations give periods of around 25 and 70 s for these waves which are in good agreement with observations.