Origin of Macrospicule and Jet in Polar Corona by A Small-scale Kinked Flux-Tube

TL;DR

This study observes a small-scale kinked flux-tube in the polar corona that triggers macrospicule and jet phenomena, supported by 2-D simulations showing reconnection-driven plasma ejections and shock waves.

Contribution

It provides new observational evidence linking small-scale flux-tube kinking to macrospicule and jet formation, complemented by numerical simulations explaining the physical mechanisms involved.

Findings

Kinked flux-tube triggers macrospicule and jet formation.

Reconnection generates velocity pulses and shock waves driving plasma ejections.

Simulations confirm the role of reconnection and shock dynamics in observed phenomena.

Abstract

We report an observation of a small scale flux-tube that undergoes kinking and triggers the macrospicule and a jet on November 11, 2010 in the north polar corona. The small-scale flux-tube emerged well before the triggering of macrospicule and as the time progresses the two opposite halves of this omega shaped flux-tube bent transversely and approached towards each other. After $\sim$ 2 minutes, the two approaching halves of the kinked flux-tube touch each-other and internal reconnection as well as energy release takes place at the adjoining location and a macrospicule was launched which goes upto a height of 12 Mm. Plasma starts moving horizontally as well as vertically upward along with the onset of macrospicule and thereafter converts into a large-scale jet which goes up to $\sim$ 40 Mm in the solar atmosphere with a projected speed of $\sim$ 95 km s$^{-1}$. We perform 2-D numerical simulation by considering the VAL-C initial atmospheric conditions to understand the physical scenario of the observed macrospicule and associated jet. The simulation results show that reconnection generated velocity pulse in the lower solar atmosphere steepens into slow shock and the cool plasma is driven behind it in form of macrospicule. The horizontal surface waves also appeared with the shock fronts at different heights, which most likely drove and spread the large-scale jet associated with the macrospicule.