Hot Explosions in the Cool Atmosphere of the Sun

TL;DR

This paper discusses recent IRIS observations revealing complex, dynamic structures in the Sun's atmosphere, especially the photosphere and chromosphere, highlighting hot plasma pockets and energy conversion processes related to magnetic reconnection.

Contribution

It introduces new IRIS observational data that challenge traditional models, showing the complexity of the solar photosphere and insights into magnetic reconnection energy transfer.

Findings

Detection of hot plasma pockets at 100,000 K in the photosphere

Confirmation of the dynamic, structured nature of the solar atmosphere

Insights into energy conversion during magnetic reconnection

Abstract

The solar atmosphere was traditionally represented with a simple one-dimensional model. Over the past few decades, this paradigm shifted for the chromosphere and corona that constitute the outer atmosphere, which is now considered a dynamic structured envelope. Recent observations by IRIS (Interface Region Imaging Spectrograph) reveal that it is difficult to determine what is up and down even in the cool 6000-K photosphere just above the solar surface: this region hosts pockets of hot plasma transiently heated to almost 100,000 K. The energy to heat and accelerate the plasma requires a considerable fraction of the energy from flares, the largest solar disruptions. These IRIS observations not only confirm that the photosphere is more complex than conventionally thought, but also provide insight into the energy conversion in the process of magnetic reconnection.