On the generation of solar spicules and Alfv\'enic waves

TL;DR

This paper investigates the origin of solar spicules and Alfvénic waves in the chromosphere, using simulations and observations to reveal how magnetic tension and ambipolar diffusion drive these phenomena.

Contribution

It demonstrates that magnetic tension amplification and ambipolar diffusion are key mechanisms in spicule formation and wave generation, providing new insights into solar atmospheric dynamics.

Findings

Spicules occur when magnetic tension is amplified and transported upward.

Ambipolar diffusion heats plasma and facilitates spicule formation.

Simulations match observations, confirming the proposed mechanism.

Abstract

In the lower solar atmosphere, the chromosphere is permeated by jets known as spicules, in which plasma is propelled at speeds of 50 to 150 kilometers per second into the corona. The origin of the spicules is poorly understood, although they are expected to play a role in heating the million-degree corona and are associated with Alfv\'enic waves that help drive the solar wind. We compare magnetohydrodynamic simulations of spicules with observations from the Interface Region Imaging Spectrograph and the Swedish 1-m Solar Telescope. Spicules are shown to occur when magnetic tension is amplified and transported upward through interactions between ions and neutrals or ambipolar diffusion. The tension is impulsively released to drive flows, heat plasma (through ambipolar diffusion), and generate Alfv\'enic waves.