Are tornado-like magnetic structures able to support solar prominence plasma?

TL;DR

This paper investigates whether tornado-like magnetic structures can support the plasma in solar prominences, using analytical modeling to explore the role of magnetic forces and flows in maintaining prominence stability.

Contribution

It introduces an analytical model demonstrating how twisted magnetic fields and poloidal flows can support prominence plasma against gravity.

Findings

Lorentz force can support cool prominence plasma

Sufficient magnetic twist is necessary for support

Poloidal flows contribute to plasma support

Abstract

Recent high-resolution and high-cadence observations have surprisingly suggested that prominence barbs exhibit apparent rotating motions suggestive of a tornado-like structure. Additional evidence has been provided by Doppler measurements. The observations reveal opposite velocities for both hot and cool plasma on the two sides of a prominence barb. This motion is persistent for several hours and has been interpreted in terms of rotational motion of prominence feet. Several authors suggest that such barb motions are rotating helical structures around a vertical axis similar to tornadoes on Earth. One of the difficulties of such a proposal is how to support cool prominence plasma in almost-vertical structures against gravity. In this work we model analytically a tornado-like structure and try to determine possible mechanisms to support the prominence plasma. We have found that the Lorentz force can indeed support the barb plasma provided the magnetic structure is sufficiently twisted and/or significant poloidal flows are present.