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We present the formation of quasi-periodic cool spicule-like jets in the solar atmosphere using 2.5-D numerical simulation in two-fluid regime (ions+neutrals) under the presence of thermal conduction and ion-neutral collision. The nonlinear, impulsive Alfvénic perturbations at the top of the photosphere trigger field aligned magnetoacoustic perturbations due to ponderomotive force. The transport of energy from Alfvén pulse to such vertical velocity perturbations due to ponderomotive force is considered as an initial trigger mechanism. Thereafter, these velocity perturbations steepen into the shocks followed by quasi-periodic rise and fall of the cool jets transporting mass in the overlying corona. This article is part of the theme issue 'Partially ionized plasma of the solar atmosphere: recent advances and future pathways'. [ABSTRACT FROM AUTHOR]

In the present paper, we describe a 2.5D (two-and-a-half-dimensional) magnetohydrodynamic (MHD) simulation that provides a detailed picture of the evolution of cool jets triggered by initial vertical velocity perturbations in the solar chromosphere. We implement random multiple velocity, V y , pulses of amplitude 20–50 km s − 1 between 1 Mm and 1.5 Mm in the Sun's atmosphere below its transition region (TR). These pulses also consist of different switch-off periods between 50 s and 300 s. The applied vertical velocity pulses create a series of magnetoacoustic shocks steepening above the TR. These shocks interact with each other in the inner corona, leading to complex localized velocity fields. The upward propagation of such perturbations creates low-pressure regions behind them, which propel a variety of cool jets and plasma flows in the localized corona. The localized complex velocity fields generate transverse oscillations in some of these jets during their evolution. We study the transverse oscillations of a representative cool jet J 1 , which moves up to the height of 6.2 Mm above the TR from its origin point. During its evolution, the plasma flows make the spine of jet J 1 radially inhomogeneous, which is visible in the density and Alfvén speed smoothly varying across the jet. The highly dense J 1 , which is triggered along the significantly curved magnetic field lines, supports the propagating transverse wave of period of approximately 195 s with a phase speed of about 125 km s−1. In the distance–time map of density, it is manifested as a transverse kink wave. However, the careful investigation of the distance–time maps of the x- and z-components of velocity reveals that these transverse waves are actually of mixed Alfvénic modes. The transverse wave shows evidence of damping in the jet. We conclude that the cross-field structuring of the density and characteristic Alfvén speed within J 1 causes the onset of the resonant conversion and leakage of the wave energy outward to dissipate these transverse oscillations via resonant absorption. The wave energy flux is estimated as approximately of 1.0 × 10 6 ergs cm − 2 s − 1 . This energy, if it dissipates through the resonant absorption into the corona where the jet is propagated, is sufficient energy for the localized coronal heating. [ABSTRACT FROM AUTHOR]

In this paper, we describe the kinematical and evolutionary properties of the impulsive cool jets in the solar atmosphere using numerical simulation by Godunov-type PLUTO code at two different quiet-Sun magnetic field strengths (B=56 gauss and B=112 gauss). These types of chromospheric jets originate due to a pressure pulse, which mimics the after-effects of the localized heating in the lower solar atmosphere. These jets may be responsible for the transport of mass and energy in the localized upper atmosphere (i.e. corona). The detection of the height–time profiles for the jets, which were developed by imposing different pressure pulses, exhibit asymmetric near-parabolic behaviour. This infers that the upward motion of the jet occurs under the influence of pressure perturbation. However, its downward motion is not only governed by the gravitational free fall, but also by the complex plasma motions near its base under the effect of counter-propagating pulses. The maximum height and lifetime of the jets with respect to the strength of the pressure pulse show a linear increasing trend. This suggests that if the extent of the heating and, thus, the pressure perturbations are longer, then more longer chromospheric jets can be triggered from the same location in the chromosphere. For a certain amplitude of pressure pulse, the strong magnetic field configuration (B=112 gauss) leads to more longer jets compared with the weaker field (B=56 gauss). This suggests that the strong magnetic field guides the pressure-pulse-driven jets more efficiency towards the higher corona. In conclusion, our model mimics the properties and evolution of the variety of the cool impulsive jets in the chromosphere (e.g. macrospicules, network jets, isolated repeated cool jets, confined and small surges, and so on.). [ABSTRACT FROM AUTHOR]