Transverse oscillations of flowing prominence threads observed with Hinode

TL;DR

This study analyzes transverse oscillations in flowing prominence threads observed with Hinode, using seismology and the thin tube approximation to estimate Alfvén speeds and magnetic field implications.

Contribution

It applies seismological analysis with the thin tube approximation to flowing prominence threads, providing lower bounds on Alfvén speeds and insights into magnetic field strengths.

Findings

Oscillatory period is minimally affected by flow.

Lower bound for Alfvén speed ranges between 120 km/s and 350 km/s.

Alfvén speeds are consistent with strong magnetic fields in active prominences.

Abstract

Recent observations with the Hinode Solar Optical Telescope display an active region prominence whose fine threads oscillate in the vertical direction as they move along a path parallel to the photosphere. A seismological analysis of this event is carried out by taking advantage of the small radius of these structures compared to the total length of magnetic field lines, i.e. by using the thin tube approximation. This analysis reveals that the oscillatory period is only slightly modified by the existence of the flow and that the difference between the period of a flowing thread and a static one is below the error bars of these observations. Moreover, although it is not possible to obtain values of the physical parameters, a lower bound for the Alfv\'en speed (ranging between 120 km s$^{-1}$ and 350 km s$^{-1}$) is obtained for each of the threads. Such Alfv\'en speeds agree with the intense magnetic fields and large densities usually found in active region prominences.