Heating at the remote footpoints as a brake on jet flows along loops in the solar atmosphere

TL;DR

This study observes a solar jet and remote footpoint heating that acts as a brake on jet flow, revealing how chromospheric evaporation influences jet dynamics and provides insights into solar atmospheric processes.

Contribution

It demonstrates that remote footpoint heating due to magnetic reconnection can decelerate solar jets, offering new understanding of jet dynamics and chromospheric evaporation effects.

Findings

Jet propagates at >100 km/s with multi-thermal components.

Remote footpoint brightenings lag jet base emissions by 60 s.

Deceleration of jet ranges from 1.5 to 3 km/s² due to remote heating.

Abstract

We report on observations of a solar jet propagating along coronal loops taken by the Solar Dynamics Observatory (SDO), the Interface Region Imaging Spectragraph (IRIS) and 1-m New Vacuum Solar Telescope (NVST). The ejecta of the jet consist of multi-thermal components and propagate with a speed greater than 100 km/s. Brightenings are found in the remote footpoints of the coronal loops having compact and round-shape in the Halpha images. The emission peak of the remote brightening in the Atmospheric Imaging Assembly (AIA) 94 \AA passband lags 60 s behind that in the jet base. The brightenings in the remote footpoints are believed to be consequences of heating by nonthermal electrons, MHD waves and/or conduction front generated by the magnetic reconnection processes of the jet. The heating in the remote footpoints leads to extension of the brightening along the loops toward the jet base, which is believed to be the chromospheric evaporation. This apparently acts as a brake on the ejecta, leading to a deceleration in the range from 1.5 to 3 km s$^{-2}$ with an error of $\sim1.0$\,km s$^{-2}$ when the chromospheric evaporation and the ejecta meet at locations near the loop apexes. The dynamics of this jet allows a unique opportunity to diagnose the chromospheric evaporation from the remote footpoints, from which we deduce a velocity in the range of 330--880 km/s.