Numerical simulations of macrospicule jets under energy imbalance conditions in the solar atmosphere

Abstract

Using numerical simulations, we study the effects of thermal conduction and radiative cooling on the formation and evolution of solar jets with some macrospicules features. We initially assume that the solar atmosphere is rarely in equilibrium through energy imbalance. Therefore, we test whether the background flows resulting from an imbalance between thermal conduction and radiative cooling influence the jets’ behaviour. In this particular scenario, we trigger the formation of the jets by launching a vertical velocity pulse localized at the upper chromosphere for the following test cases: (i) adiabatic case; (ii) thermal conduction case; (iii) radiative cooling case; and (iv) thermal conduction + radiative cooling case. According to the test results, the addition of the thermal conduction results in smaller and hotter jets than in the adiabatic case. On the other hand, the radiative cooling dissipates the jet after reaching the maximum height (≈5.5 Mm), making it shorter and colder than in the adiabatic and thermal conduction cases. Besides, the flow generated by the radiative cooling is more substantial than that caused by the thermal conduction. Despite the energy imbalance of the solar atmosphere background, the simulated jet shows morphological features of macrospicules. Furthermore, the velocity pulse steepens into a shock that propagates upward into a solar corona that maintains its initial temperature. The shocks generate the jets with a quasi-periodical behaviour that follows a parabolic path on time–distance plots consistent with macrospicule jets’ observed dynamics.

Influence of the Magnetic Field Topology in the Evolution of Small-Scale Two-Fluid Jets in the Solar Atmosphere

“…Meantime, the Type II spicules, which could be generated due to magnetic reconnection, reach heights from 1000 to 7000 km above the chromosphere, in a range of vertical speeds between 40 km/s and 300 km/s, with the bulk between 50 and 150 km/s, lifetimes from 10 to 150 s, with characteristic diameters less than 200 km, temperatures of approximately 10 4 K [5,13,[19][20][21][22]. Moreover, the macrospicules can reach heights of 7-70 Mm and speeds of 10-150 km/s, and they can have lifetimes of 3-45 min, according to observations and numerical simulations [14,23,24]. Finally, there is also another complex chromospheric ejection, known as surges, which are seen as darkenings in the blue/red wings of the line with line-of-sight (LOS) apparent velocities of a few to several tens of km/s on areas with projected lengths of 10-50 Mm [25].…”

“…Actually, the magnetic conditions of the chromosphere are complex. However, in some simulations, such as in studies [24,43], there are a few bounded regions where some jets evolve within field lines that vary smoothly. Therefore, the point of the current simulations paper was to explore these conditions in a more general context to have as a control test in a magnetically uniform environment.…”

Small-scale solar jet formation and their associated waves and instabilities

“…Numerical simulations of the rebound shock model have accurately reproduced many of the observed characteristics of type I spicules and macrospicules under adiabatic and nonadiabatic conditions (see, e.g. Murawski & Zaqarashvili, 2010;Murawski et al, 2011;González-Avilés et al, 2021). In these studies, the authors modelled the dynamics of spicules by solving the 2D MHD equations.…”

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

“…They are known as macrospicules. They [27][28][29][30][31]. These comparatively larger spicules may be observed in the polar region of the coronal holes.…”