# The Magnetic Origin of Solar Campfires

**Authors:** Navdeep K. Panesar, Sanjiv K. Tiwari, David Berghmans, Mark C. M. Cheung, Daniel Muller, Frederic Auchere, Andrei Zhukov  
**arXiv:** [2110.06846](https://arxiv.org/abs/2110.06846)  
**Date:** 2021-10-13  
**Summary page:** https://www.summarizepaper.com/en/paper/2110.06846v1/

## Key points

- Solar campfires are small-scale heating events observed by the Extreme Ultraviolet Imager (EUI) onboard Solar Orbiter.
- The authors investigated the magnetic origin of 52 randomly selected campfires in the quiet solar corona using EUI 174\AA\ images, EUV images from SDO/AIA, and line-of-sight magnetograms from SDO/HMI.
- Most of the campfires are rooted at the edges of photospheric magnetic network lanes and reside above the neutral line between majority-polarity magnetic flux patch and a merging minority-polarity flux patch, with a flux cancelation rate of $\sim$10$^{18}$Mx hr$^{-1}$.
- "Campfire" is a general term that includes different types of small-scale solar dynamic features containing sufficient magnetic energy ($\sim$10$^{26}$ - 10$^{27}$ erg) to heat the solar atmosphere locally to 0.5--2.5MK.
- Their lifetimes range from about a minute to over an hour, with most having a lifetime of $<$10 minutes. The average lengths and widths of campfires are 5400 $\pm$ 2500 km and 1600 $\pm$ 640 km respectively.
- Magnetic flux ropes may be ubiquitous in the solar atmosphere and not limited to coronal jets and larger scale eruptions that make CMEs; furthermore, magnetic flux cancelation is fundamental for forming and triggering most campfires.
- This study provides new insights into understanding how small-scale heating events occur in the Sun's atmosphere and may help improve our understanding of its magnetic field as well as its impact on space weather.
- The authors' findings could also have implications for future space missions as they suggest these small scale events are more common than previously thought which could pose a risk to spacecraft orbiting around it.

## Summary

Solar campfires are small-scale heating events that have recently been observed by the Extreme Ultraviolet Imager (EUI) onboard Solar Orbiter. In this study, the authors investigate the magnetic origin of 52 randomly selected campfires in the quiet solar corona using EUI 174\AA\ images, EUV images from SDO/AIA, and line-of-sight magnetograms from SDO/HMI. The authors find that most of the campfires are rooted at the edges of photospheric magnetic network lanes and reside above the neutral line between majority-polarity magnetic flux patch and a merging minority-polarity flux patch, with a flux cancelation rate of $\sim$10$^{18}$Mx hr$^{-1}$. Some of the campfires occur repeatedly from the same neutral line, and in most instances they are preceded by a cool-plasma structure analogous to minifilaments in coronal jets. Although many campfires have complex structures, most resemble small-scale jets, dots or loops. The authors suggest that "campfire" is a general term that includes different types of small-scale solar dynamic features containing sufficient magnetic energy ($\sim$10$^{26}$ - 10$^{27}$ erg) to heat the solar atmosphere locally to 0.5--2.5MK. Their lifetimes range from about a minute to over an hour, with most having a lifetime of $<$10 minutes. The average lengths and widths of campfires are 5400 $\pm$ 2500 km and 1600 $\pm$ 640 km respectively. The observations suggest that magnetic flux ropes may be ubiquitous in the solar atmosphere and not limited to coronal jets and larger scale eruptions that make CMEs; furthermore, magnetic flux cancelation is fundamental for forming and triggering most campfires. This study provides new insights into understanding how small-scale heating events occur in the Sun's atmosphere and may help improve our understanding of its magnetic field as well as its impact on space weather. The authors' findings could also have implications for future space missions as they suggest these small scale events are more common than previously thought which could pose a risk to spacecraft orbiting around it. Overall this study highlights the importance of studying small scale solar dynamic features and their magnetic origins to advance our knowledge of the Sun's effects on Earth.