A Three-dimensional Magnetohydrodynamic Simulation of the Formation of Solar Chromospheric Jets with Twisted Magnetic Field Lines

Abstract

This paper presents a three-dimensional simulation of chromospheric jets with twisted magnetic field lines. Detailed treatments of the photospheric radiative transfer and the equation of states allow us to model realistic thermal convection near the solar surface, which excites various MHD waves and produces chromospheric jets in the simulation. A tall chromospheric jet with a maximum height of 10-11 Mm and lifetime of 8-10 min is formed above a strong magnetic field concentration. The magnetic field lines are strongly entangled in the chromosphere, which helps the chromospheric jet to be driven by the Lorentz force. The jet exhibits oscillatory motion as a natural consequence of its generation mechanism. We also find that the produced chromospheric jet forms a cluster with a diameter of several Mm with finer strands. These results imply a close relationship between the simulated jet and solar spicules.

I. Jet Formation and Evolution Due to 3D Magnetic Reconnection

“…This result provides a simple explanation and is in contrast with that in Martínez-Sykora et al (2017), where, using 2D simulations, the formation of spicules is explained in terms of the amplification of the magnetic tension and the interaction between ions and neutrals. In our simulation we show that, even if magnetic tension is important, the magnetic pressure, which is related to full Lorentz force being important as well, which is consistent with the results obtained in the simulations of vortex tubes (Kitiashvili et al 2013) and in the formation of solar chromospheric jets (Iijima & Yokoyama 2017), a quantitative distinction between the components of the different forces involved would require the development of new analysis tools for time-dependent structures.…”

Chromospheric polarimetry through multiline observations of the 850 nm spectral region III: Chromospheric jets driven by twisted magnetic fields

“…from -2 to 14 Mm above the solar surface. The setup of this simulation is explained in Iijima & Yokoyama (2017) although we describe below some of its properties for the sake of clarity.…”

“…We focus on the region enclosed by a box (see Figure 1) that is centred on the chromospheric jet studied in Iijima & Yokoyama (2017). This feature has a maximum height of 10 Mm, and its core is hotter than its surroundings at chromospheric layers.…”

“…There is a strong concentration at lower heights (leftmost panel) that occupies larger areas as we examine lines that form higher in the atmosphere. Moreover, there is a thin region that corresponds to magnetic field lines that extend beyond the core of the jet (see sky blue lines at the left part of the structure presented in Figure 8 of Iijima & Yokoyama (2017)). This thin region is located further from the centre of the jet when we scan higher heights.…”

“…In this publication, we focus on the MHD simulation of a chromospheric jet with complex plasma flows and twisted magnetic field lines by Iijima (2016); Iijima & Yokoyama (2017). In this simulation, the thermal convection near the solar surface excites various MHD waves and generates chromospheric jets rooted in magnetic field concentrations.…”