Transverse oscillations in solar spicules induced by propagating Alfvenic pulses

TL;DR

This study models how localized Alfvenic pulses can excite transverse oscillations in solar spicules, showing that these waves propagate, dampen, and match observed oscillation periods, advancing understanding of solar atmospheric dynamics.

Contribution

It introduces a detailed MHD model of Alfvenic pulse excitation in spicules, incorporating gravity, stratification, and shear, revealing wave propagation and damping mechanisms.

Findings

Oscillation periods match observations.

Alfvenic waves propagate and dampen along spicules.

Damping time increases with decreasing k_b.

Abstract

The excitation of Alfvenic waves in the solar spicules due to the localized Alfvenic pulse is investigated. A set of incompressible MHD equations in two dimensional $x-z$ plane with steady flows and sheared magnetic fields is solved. Stratification due to gravity and transition region between chromosphere and corona are taken into account. An initially localized Alfvenic pulse launched below the transition region can penetrate from transition region into the corona. We show that the period of transversal oscillations is in agreement with those observed in spicules. Moreover, it is found that the excited Alfvenic waves spread during propagation along the spicule length, and suffer efficient damping of the oscillations amplitude. The damping time of transverse oscillations elongated with decrease in k_b values.