Can the Solar p-modes Contribute to the High-frequency Transverse Oscillations of Spicules?

Abstract

Lateral motions of spicules serve as vital indicators of transverse waves in the solar atmosphere, and their study is crucial for understanding the wave-heating process of the corona. Recent observations have focused on high-frequency transverse waves (periods < 100 s), which have the potential to transport sufficient energy for coronal heating. These high-frequency spicule oscillations are distinct from granular motions, which have much longer timescales of 5–10 minutes. Instead, it is proposed that they are generated through the mode conversion from high-frequency longitudinal waves that arise from a shock-steepening process. Therefore, these oscillations may not solely be produced by the horizontal buffeting motions of granulation but also by the leakage of p -mode oscillations. To investigate the contribution of p -modes, our study employs a two-dimensional magneto-convection simulation spanning from the upper convection zone to the corona. During the course of the simulation, we introduce a p -mode-like driver at the bottom boundary. We reveal a notable increase in the mean velocity amplitude of the transverse oscillations in spicules, ranging from 10%–30%, and attribute this to the energy transfer from longitudinal to transverse waves. This effect results in an enhancement of the estimated energy flux by 30%–80%.

Keywords

• Solar spicules
• Solar oscillations
• Solar chromosphere
• Solar coronal heating
• Radiative magnetohydrodynamics