Speaker
Description
Studying the evolution of the energy budget involved in solar eruptions is central, particularly to understanding their early stages, but also for the subsequent interplanetary expansion. For this purpose, it is important to quantify the thermal energy evolution of erupting plasma, compare it with the expected adiabatic cooling, and determine at least approximately how energy is partitioned among its kinetic, potential, and thermal components. This can be done by combining observations acquired in different spectral bands and possibly from different observation points.
Here we report on a prominence eruption that was observed simultaneously by the multichannel Metis Coronagraph onboard the Solar Orbiter mission, and by the Lyman-alpha Solar Telescope (LST) onboard the Advanced Space-based Solar Observatory (ASO-S) from different perspectives. The prominence appeared as a very bright and elongated arch propagating southward in Metis UV Lyman-alpha images, but it is much weaker in Metis visible light (VL) images. The Solar Disk Imager (SDI) of LST observes the prominence lifting from the southwest solar limb, with the south leg fixed onto the Sun as it expands.
The multichannel observations of Metis enable us to measure the electron density, the mass, and the velocity of the prominence. On the other hand, by taking advantage of Lyman-alpha observations, we applied a new approach independent of the UV calibration to estimate the temperature evolution of two segments of the prominence. The results obtained are in good agreement with what can be measured with the standard technique based on the evolution of the total Lyman-alpha intensity, considering both the radiative and collisional components. Resulting measurements of the excess thermal energy suggest that a significant heating is going on during the eruption.
