Abstract

We report on a dynamical event observed in a quiescent prominence on 2007 November 8: a well-formed dark "bubble" with a bright core rose vertically through the prominence without causing it to erupt. This event was observed in Hα and He I 1083 nm with the instruments of the Mauna Loa Solar Obser... Show moreWe report on a dynamical event observed in a quiescent prominence on 2007 November 8: a well-formed dark "bubble" with a bright core rose vertically through the prominence without causing it to erupt. This event was observed in Hα and He I 1083 nm with the instruments of the Mauna Loa Solar Observatory. The dark bubble had a size of over 40" and rose from the prominence base, at an average speed of ~12 km s⁻¹, forming a bright compression front as it traversed the prominence. It finally assumed a "keyhole" shape before fading. The bright core embedded in the dark bubble was observed to rise from the solar limb, accelerating from ~12 to ~20 km s⁻¹, leaving a thin trail of material behind. Subsequent observations indicate that this was not an exceptional event, but rather that similar disturbances do occur occasionally in prominences without disrupting them. In this Letter we present the November 8 observations, and propose a possible interpretation of the physical mechanism behind these dynamic events. Show less