Magnetic Topology of a Long-Lived Coronal Condensation Site Lasting Eight Months

It is well known that cool material, such as prominences or coronal rain, can form in-situ by condensation of hot coronal plasma due to a runaway radiative cooling instability (a.k.a. thermal non-equilibrium). Recent observations and numerical simulations suggest that such condensations are quite common, but in quiet-Sun regions, they occur preferentially in locations where magnetic field is weak (e.g., null points) or discontinuous (e.g., current sheets). Such events usually have short lifetimes of hours to days. Surprisingly, we observed a high-latitude condensation site lasting over eight months in 2014 with recurrent and episodic condensations fueling a funnel-shaped prominence. We analyze the coronal magnetic topology to investigate the necessary condition of such a long-lived condensation site. We find that the site was directly above a poleward photospheric flux surge when the polar field polarity was close to its solar cycle reversal. The large-scale magnetic cancellation front may have sustained interchange reconnection at this location, creating suitable conditions for coronal plasma condensation.