Formation Dynamics of a Rotating Solar Spicule-like Event and Associated Energy-Mass Transport

Abstract

We performed three-dimensional radiative magnetohydrodynamic(3D RMHD) simulations in an upward-directed (positive-polarity) open magnetic field with an initial background strength of 10 G. We identified vortex-associated spicule-like events and carried out a detailed analysis of one representative event. Prior to the formation of this spicule-like event, a photospheric vortex appears and twists the magnetic field lines, then develops upward into higher atmospheric layers, forming a magnetic tornado system. This event is generated during this process. At the periphery of this magnetic tornado, twisted magnetic field lines with negative vertical components reconnect with both external positive-polarity background fields and central positive-polarity fields. The magnetic reconnection sites rise and rotate together with the developed magnetic tornado, and many jet-like substructures in this event are closely associated with plasma upward ejections from these reconnection regions. A vertical force analysis shows that, for this event, plasma uplift in the photosphere and lower chromosphere is dominated by the pressure-gradient force, whereas in the upper chromosphere, the Lorentz force gradually becomes dominant. At a height of about 4 Mm above the solar surface, this event produces a mean upward mass flux density on the order of $10^{-7}~{\rm kg~m^{-2}~s^{-1}}$ and a mean upward Poynting flux density of approximately $525~{\rm W~m^{-2}}$. The wave-mode decomposition results show that the energy transport associated with the rotational spicule-like event is dominated by the Alfvén mode. Alfvén waves, fast-mode waves, and slow-mode waves carry energy into the lower corona in an approximate ratio of $10:7:3$.