Analysis of 3D plasma motions in a chromospheric jet formed due to magnetic reconnection

TL;DR

This study uses 3D MHD simulations to analyze plasma motions in a chromospheric jet formed by magnetic reconnection, revealing transverse oscillations and torsional motions consistent with observations of Type II spicules.

Contribution

It provides a detailed analysis of transverse displacements and rotational motions in a simulated chromospheric jet, linking magnetic reconnection to observed jet dynamics.

Findings

Transverse oscillations match observed spicule behavior.

Rotational motions cause red-blue Doppler shifts across the jet.

Simulation results support magnetic reconnection as jet formation mechanism.

Abstract

Within the framework of resistive MHD, implementing the C7 equilibrium atmosphere model and a 3D potential magnetic field realistic configuration, we simulate the formation of a plasm jet with the morphology, upward velocity up to 130 km/s and timescale formation between 60 and 90 s after beginning of simulation, similar to those expected for Type II spicules. Initial results of this simulation were published in Paper (e.g., Gonz\'alez-Avil\'es et al. 2018) and present paper is devoted to the analysis of transverse displacements and rotational type motion of the jet. Our results suggest that 3D magnetic reconnection may be responsible for the formation of the jet in Paper (Gonz\'alez-Avil\'es et al. 2018). In this paper, by calculating times series of the velocity components $v_x$ and $v_y$ in different points near to the jet for various heights we find transverse oscillations in agreement with spicule observations. We also obtain a time-distance plot of the temperature in a cross-cut at the plane $x=$0.1 Mm and find significant transverse displacements of the jet. By analyzing temperature isosurfaces of $10^{4}$ K with the distribution of $v_x$, we find that if the line-of-sight (LOS) is approximately perpendicular to the jet axis then there is both motion towards and away from the observer across the width of the jet. This red-blue shift pattern of the jet is caused by rotational motion, initially clockwise and anti-clockwise afterwards, which could be interpreted as torsional motion. From a nearly vertical perspective of the jet the LOS velocity component shows a central blue-shift region surrounded by red-shifted plasma.