Quasi-periodic spicule-like cool jets driven by Alfvén pulses

Abstract

We perform a 2.5 dimensional magnetohydrodynamic (MHD) simulation to understand a comprehensive view of the formation of spicule-like cool jets due to initial transverse velocity pulses akin to Alfvén pulses in the solar chromosphere. We invoke multiple velocity (Vz) pulses between 1.5 and 2.0 Mm in the solar atmosphere, which create the initial transverse velocity perturbations. These pulses transfer energy non-linearly to the field aligned perturbations due to the ponderomotive force. This physical process further creates the magnetoacoustic shocks followed by quasi-periodic plasma motions in the solar atmosphere. The field aligned magnetoacoustic shocks move upward which subsequently cause quasi-periodic rise and fall of the chromospheric plasma into the overlying corona as a thin and cool spicule-like jets. The magnitude of the initial applied transverse velocity pulses are taken in the range of 50-90 km s−1. These pulses are found to be strong enough to generate the spicule-like jets. We analyse the evolution, kinematics and energetics of these spicule-like jets. We find that the transported mass flux and kinetic energy density are substantial in the localized solar-corona. These mass motions generate in situ quasi-periodic oscillations on the scale of ≃ 4.0 min above the transition region.

Alfvén pulse driven spicule-like jets in the presence of thermal conduction and ion-neutral collision in two-fluid regime

“…The complex magnetic field structuring and highly dynamic nature of the Sun's chromosphere permit the genesis of numerous high speed jet-like plasma ejecta at different time and spatial scales [1][2][3][4][5][6][7][8]. These cool spicule-like jets are significant dynamical plasma processes that may be accompanied by various types of waves, oscillations, instabilities etc.…”

“…These cool spicule-like jets are significant dynamical plasma processes that may be accompanied by various types of waves, oscillations, instabilities etc. in the Sun's atmosphere [5,6,[9][10][11][12][13]. Such confined and cool jet like features may be one of the possible sources to carry energy and mass from the inner layers (i.e.…”

“…transition region and corona). These jet-like phenomena evoked the scientific research, keeping in view the advent of many space-borne and ground-based, high-resolution solar observations, as well as theoretical/numerical modelling [1,2,6,[14][15][16][17][18][19][20][21]. These jets may also have impulsive origin, and they could exhibit quasi-periodic upward and downward plasma motions along their spine in the localized solar atmosphere.…”

“…These jets may also have impulsive origin, and they could exhibit quasi-periodic upward and downward plasma motions along their spine in the localized solar atmosphere. There are several observational and theoretical results available, which frequently describe their origin, evolution, physical properties and associated plasma processes [6][7][8]14,22]. However, their exact triggering mechanisms are still unclear, thereby detailed investigation is always an essential requirement using observations with high resolution observations as well as extensive numerical modelling.…”

“…As a result, eventually an evolution of the magnetoacoustic shock enables the motion of the plasma in the form of cool jets. In such models, the applied pulses act as a driver and create localized heating or transfer of momentum resulting in shocks and generating the jet-like features [1,4,6,14,22,44,47,48]. The process generally proposed as the agents causing the formation of cool spicular jets and other chromospheric cool plasma ejecta (e.g.…”