Origin of Both the Fast Hot Jet and the Slow Cool Jet from Magnetic Flux Emergence and Advection in the Solar Transition Region

TL;DR

This study uses numerical simulations to explore how magnetic flux emergence and advection in the solar transition region produce both fast hot jets and slow cool jets, shedding light on their formation mechanisms.

Contribution

It demonstrates that magnetic reconnection driven by supergranular convection can generate both hot and cool jets, revealing their different driving forces and dependence on magnetic flux.

Findings

Fast hot jets are driven by Lorentz force during reconnection.

Slow cool jets are initiated by an initial Lorentz force kick.

Jet characteristics vary with the amount of emerging magnetic flux.

Abstract

In the solar atmosphere, the jets are ubiquitous and found to be at various spatia-temporal scales. They are significant to understand energy and mass transport in the solar atmosphere. Recently, the high-speed transition region jets are reported from the observation. Here we conduct a numerical simulation to investigate the mechanism in their formation. Driven by the supergranular convection motion, the magnetic reconnection between the magnetic loop and the background open flux occurring in the transition region is simulated with a two-dimensional magnetohydrodynamics model. The simulation results show that not only a fast hot jet, much resemble the found transition region jets, but also a adjacent slow cool jet, mostly like classical spicules, is launched. The force analysis shows that the fast hot jet is continually driven by the Lorentz force around the reconnection region, while the slow cool jet is induced by an initial kick through the Lorentz force associated with the emerging magnetic flux. Also, the features of the driven jets change with the amount of the emerging magnetic flux, giving the varieties of both jets. These results will inspire our understanding of the formation of the prevalence of both the fast hot jet and slow cool jet from the solar transition region and chromosphere.