Oscillations and Waves in Solar Spicules

Abstract

Since their discovery, spicules have attracted increased attention as energy/mass bridges between the dense and dynamic photosphere and the tenuous hot solar corona. Mechanical energy of photospheric random and coherent motions can be guided by magnetic field lines, spanning from the interior to the upper parts of the solar atmosphere, in the form of waves and oscillations. Since spicules are one of the most pronounced features of the chromosphere, the energy transport they participate in can be traced by the observations of their oscillatory motions. Oscillations in spicules have been observed for a long time. However the recent high-resolution and high-cadence space and ground based facilities with superb spatial, temporal and spectral capacities brought new aspects in the research of spicule dynamics. Here we review the progress made in imaging and spectroscopic observations of waves and oscillations in spicules. The observations are accompanied by a discussion on theoretical modelling and interpretations of these oscillations. Finally, we embark on the recent developments made on the presence and role of Alfvén and kink waves in spicules. We also address the extensive debate made on the Alfvén versus kink waves in the context of the explanation of the observed transverse oscillations of spicule axes.

Transverse Oscillations in Chromospheric Mottles

“…An excellent review on the topic is given by Zaqarashvili & Erdélyi (2009). Kink waves have also been recently observed in active region fibrils (Pietarila et al 2011).…”

Resonant Alfvén waves in partially ionized plasmas of the solar atmosphere

“…For example, Alfvénic transverse waves propagating in magnetic waveguides of the solar corona were first observed by Tomczyk et al (2007) and Tomczyk & McIntosh (2009) using the Coronal Multichannel Polarimeter (CoMP), and more recently by McIntosh et al (2011) using SDO/AIA. In chromospheric spicules, the presence of Doppler oscillations is known for more than 40 years (see the review by Zaqarashvili & Erdélyi 2009). Recent observations of Alfvénic transverse waves in spicules have been reported by, e.g, De Pontieu et al (2007), Zaqarashvili et al (2007), Kim et al (2008), He et al (2009a,b), Okamoto & De Pontieu (2011).…”

Numerical simulations of solar macrospicules

“…Spicules are thin, cool, and dense structures that are observed in the solar limb (Beckers 1968(Beckers , 1972Suematsu 1998;Sterling 2000;Zaqarashvili & Erdélyi 2009). Type I spicules are seen to be formed at an altitude of about 2000 km where they reveal a speed of 25 km s −1 , reach a maximum level and then either disappear or fall off to the photosphere.…”