On the origin of intergranular jets

TL;DR

This study investigates the origin and characteristics of intergranular jets in the solar photosphere, linking them to vortex tubes, magnetic fields, and granular fragmentation, and suggests their potential role in solar energy and mass transport.

Contribution

It reveals that intergranular jets are associated with vortex tubes and granular fragmentation, highlighting their prevalence and possible significance in solar atmospheric dynamics.

Findings

Intergranular jets are linked to vortex tubes and granular fragmentation.

Jets are smaller, weaker, but more numerous than known solar jets.

These tiny jets may significantly contribute to solar energy and mass flux.

Abstract

We observe that intergranular jets, originating in the intergranular space surrounding individual granules, tend to be associated with granular fragmentation, in particular, with the formation and evolution of a bright granular lane (BGL) within individual granules. The BGLs have recently been identified as vortex tubes by Steiner et al. We further discover the development of a well-defined bright grain located between the BGL and the dark intergranular lane to which it is connected. Signatures of a BGL may reach the lower chromosphere and can be detected in off-band \ha images. Simulations also indicate that vortex tubes are frequently associated with small-scale magnetic fields. We speculate that the intergranular jets detected in the NST data may result from the interaction between the turbulent small-scale fields associated with the vortex tube and the larger-scale fields existing in the intergranular lanes. The intergranular jets are much smaller and weaker than all previously known jet-like events. At the same time, they appear much more numerous than the larger events, leading us to the speculation that the total energy release and mass transport by these tiny events may not be negligible in the energy and mass-flux balance near the temperature minimum atop the photosphere. The study is based on the photospheric TiO broadband (1.0 nm) filter data acquired with the 1.6 m New Solar Telescope (NST) operating at the Big Bear Solar Observatory. The data set also includes NST off-band \ha images collected through a Zeiss Lyot filter with a passband of 0.025 nm.