The Formation of Solar Prominences: Plasma Origin and Mechanisms

TL;DR

This review synthesizes current understanding of solar prominence formation, emphasizing magnetic configurations and plasma mechanisms like injection, levitation, evaporation--condensation, and in-situ condensation, with a focus on recent numerical and observational advances.

Contribution

It provides a comprehensive classification and analysis of prominence formation mechanisms, integrating recent simulation results and observational data to clarify their roles and coexistence.

Findings

Evaporation--condensation is a key formation mechanism supported by simulations.

Recent high-resolution observations validate multiple formation scenarios.

Magnetic reconnection plays a significant role in in-situ condensation processes.

Abstract

Solar prominences, or solar filaments, are cool and dense plasma structures in the hot solar corona, whose formation mechanisms have remained a fundamental challenge in solar physics. This review provides a comprehensive overview of the current theoretical, numerical, and observational understanding of prominence formation, with a focus on the origin of the dense plasma component. We begin by summarizing the magnetic field configurations that enable prominence support, followed by a classification of four representative plasma formation mechanisms: injection, levitation, evaporation--condensation, and in-situ condensation. Each mechanism is analyzed in terms of its physical basis, numerical realizations, and observational diagnostics. A central focus is placed on the evaporation--condensation scenario, which has seen significant development over the past decade through numerical simulations. We also discuss recent progress in modeling in-situ condensation triggered by magnetic reconnection and levitation dynamics. Throughout, we emphasize the complementary nature of different mechanisms and their potential coexistence in forming and maintaining prominence mass. Observational constraints and recent high-resolution data are reviewed to assess the physical plausibility of each mechanism. We conclude by highlighting open questions and future directions in connecting multi-scale physical processes to the observed diversity of prominence behaviors.