By: V. Jerčić and R. Keppens
Prominences are impressive, large-scale structures in the Sun’s corona (the uppermost layer of the Sun’s atmosphere). Like clouds on Earth, they can form via in-situ condensation processes. This condensation can be triggered by plasma evaporation from lower layers of the Sun’s atmosphere, while the local instability driving the condensation is known as thermal instability. Unlike clouds on Earth, these structures span great distances while composed of multiple fine structures on the scale of only hundreds of kilometers. They exhibit various types of motion, and some of them can even result in violent eruptions. In case the effects of the eruption reach Earth, they can have huge economic consequences.
If properly analyzed and understood, prominences can act as a precursor for such events. Even though they have been studied for decades, there are still a lot of things we don't know about them. With this research, we aimed to understand the very nature of prominences as governed by their formation process.
Figure 1. An observed solar prominence (top left) on the basis of which we construct our numerical representation (top right), and apply the range of formation experiments. The response of the prominence (bottom panel) is evident in its length, extending from 10-20 Mm in the first row to almost the full extent of our domain in the final row.
We were intrigued by how exactly evaporation-condensation proceeds, and what the mass and energy exchange is like between the prominence and the regions where they are rooted, most notably the chromosphere and the transition region (lower layers of the Sun’s atmosphere). Our research relied on heavy numerical simulations that required a significant amount of computing power (simulations of prominences and their formation ran on more than 300 hundred cores). With the state-of-the-art Tier-2 (Genius) resources made available to researchers by the Vlaams Supercomputer Centrum (VSC).
"Our research relied on heavy numerical simulations that required a significant amount of computing power (simulations of prominences and their formation ran on more than 300 hundred cores). With the state-of-the-art Tier-2 (Genius) resources made available to researchers by the Vlaams Supercomputer Centrum (VSC)"
We were able to describe how the prominence responds to the conditions driving their formation. We established that the early formation processes can directly influence the longevity of the prominence by regulating the full life cycle from the rate of evaporation to the total mass achieved, moreover, affecting also the rate of drainage. When considered over extended periods of time, ranging from days to weeks, these processes must have a crucial role in determining the life span of a prominence.
Read the full publication in the Astronomy & Astrophysics (A&A) here