Velocity vectors of a quiescent prominence observed by Hinode/SOT and the MSDP (Meudon)

TL;DR

This study combines high-resolution Hinode/SOT and MSDP observations to measure the velocity vectors of a quiescent solar prominence, revealing insights into its magnetic structure and dynamics.

Contribution

It provides the first combined measurement of transverse and Doppler velocities in a quiescent prominence using simultaneous Hinode/SOT and MSDP data.

Findings

Doppler shifts reach up to 15 km/s at prominence edges.

Transverse velocities are comparable to Doppler velocities.

Vertical structures may be due to dips in horizontal magnetic fields.

Abstract

The dynamics of prominence fine structures is a challenge to understand the formation of cool plasma prominence embedded in the hot corona. Recent observations from the high resolution Hinode/SOT telescope allow us to compute velocities perpendicularly to the line-of-sight or transverse velocities. Combining simultaneous observations obtained in H-alpha with Hinode/SOT and the MSDP spectrograph operating in the Meudon solar tower we derive the velocity vectors of a quiescent prominence. The velocities perpendicular to the line-of-sight are measured by time slice technique, the Dopplershifts by the bisector method. The Dopplershifts of bright threads derived from the MSDP reach 15 km/s at the edges of the prominence and are between +/- 5 km/s in the center of the prominence. Even though they are minimum values due to seeing effect, they are of the same order as the transverse velocities. These measurements are very important because they suggest that the verticalstructures shown in SOT may not be real vertical magnetic structures in the sky plane. The vertical structures could be a pile up of dips in more or less horizontal magnetic field lines in a 3D perspective, as it was proposed by many MHD modelers. In our analysis we also calibrate the Hinode H-alpha data using MSDP observations obtained simultaneously.