The spectrum of kink-like oscillations of solar photospheric magnetic elements

¹ INAF – Osservatorio Astronomico di Roma, 00040 Monte Porzio Catone ( RM), Italy
e-mail: marco.stangalini@inaf.it
² Universita degli Studi di Roma Tor Vergata, 00133 Roma, Italy
³ INAF – Istituto di Astrofisica e Planetologia Spaziali, 00133 Roma, Italy

Received: 28 June 2013
Accepted: 8 October 2013

Abstract

Recently, the availability of new high spatial and temporal resolution observations of the solar photosphere has allowed for the study of the oscillations in small magnetic elements. Small magnetic elements have been found to host a rich variety of oscillations detectable as intensity, longitudinal, or transverse velocity fluctuations that have been interpreted as magneto-hydrodynamic (MHD) waves. Small magnetic elements, at or below the current spatial resolution achieved by modern solar telescopes, are thought to play a relevant role in the energy budget of the upper layers of the Sun’s atmosphere, as they are found to cover a significant fraction of the solar photosphere. Unfortunately, the limited temporal length and/or cadence of the data sets or the presence of seeing-induced effects have prevented accurate estimates of the power spectra of kink-like oscillations in small magnetic elements so far. Motivated by this, we studied kink-like oscillations in small magnetic elements, by exploiting very long duration and high cadence data acquired with the Solar Optical Telescope on board the Hinode satellite. In this paper, we present the results of a statistical study of the power spectral density of kink-like oscillations. We found that small magnetic elements exhibit a large number of spectral features in the range 1−12 mHz. Most of these spectral features are not shared among magnetic elements rather they represent a unique signature of each magnetic element itself.