Three Types of Solar Coronal Rain during Magnetic Reconnection between Open and Closed Magnetic Structures

Abstract

Coronal rain (CR) is a crucial part of the mass cycle between the corona and chromosphere. It includes flare-driven CR and two types of quiescent CR, along nonflaring active region closed loops and along open structures, separately, labeled as type I, type II, and type III CR, respectively. Among them, type I and type III CR are generally associated with magnetic reconnection. In this study, employing data taken by the Solar Dynamics Observatory and the Solar Upper Transition Region Imager on 2022 October 11, we report three types of CR during an interchange reconnection between open and closed magnetic field structures above the southeastern solar limb. The open and closed structures converge, with the formation of the current sheet at the interface, and reconnect. The newly formed closed and open structures then recede from the reconnection region. During the reconnection, coronal condensation occurs along the reconnecting closed loops and falls toward the solar surface along both loop legs, as type II CR. Subsequently, condensation happens in the newly formed closed loops and moves down toward the solar surface along both loop legs, as type I CR. Magnetic dips of the reconnecting open structures form during the reconnection. In the dips, condensation occurs and propagates along the open structures toward the solar surface as type III CR. Our results suggest that the reconnection rate may be crucial for the formation of type I and type III CR during reconnection.

Keywords

• Solar magnetic reconnection
• Plasma physics
• Solar ultraviolet emission
• Solar corona
• Solar magnetic fields