Speaker
Description
First Name: Clara
Last Name: Froment
Email Address: clara.froment@cnrs-orleans.fr
Affiliation: LPC2E/CNRS
All Authors: Clara Froment and Sophie Masson
Abstract: We report the detection of thermal non-equilibrium (TNE) cycles in a pseudo-streamer observed with SDO/AIA. TNE is an ubiquitous mechanism in the solar atmosphere, especially in coronal loops. These evaporation and condensation cycles are induced by a quasi-steady stratified heating. Long-period EUV pulsations and coronal rain are two manifestations of TNE. There are recent reports of coronal rain at open-closed boundaries such a fan-spine topologies and pseudo-streamers. However, no definite conclusions were drawn on the physical mechanisms driving the coronal rain events. The event we study here has all the characteristics of previous TNE events reported in coronal loops: periodic EUV pulses appearing sequentially in the different channels, according to their peak temperature response order and coronal rain showers by the end of the cooling phases. We further show that the TNE cycles occur both in the closed and in the open field of the pseudo-streamer. Our observations support the findings of recent numerical works showing that TNE can also occur in open field and at open-closed boundaries. In parallel, interchange reconnection occurs gradually all along the open-closed boundary as seen in EUV and with a PFSS modeling. This observation opens further perspectives for the understanding of TNE in the solar atmosphere and its potential implication for the solar wind. Indeed, TNE could also inject mass and energy into the solar wind by its interplay with interchange reconnection.