SDO/AIA Detection of Solar Prominence Formation within a Coronal Cavity |
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Thomas Berger Submitted: 2012-08-16 18:17
We report the first analyses of SDO/AIA observations of the formation of a quiescent polar crown prominence in a coronal cavity. The He II 304 Å (log Tmax ~ 4.8 K) data show both the gradual disappearance of the prominence due to vertical drainage and lateral transport of plasma followed by the formation of a new prominence some 12 hours later. The formation of the prominence is preceded by the appearance of a bright emission ''cloud'' in the central region of the coronal cavity. The peak brightness of the cloud progressively shifts in time from the Fe XIV 211 Å channel, through the Fe XII 193 Å channel, to the Fe IX 171 Å channel (log Tmax ~ 6.2, 6.1, 5.8 K, respectively) while simultaneously decreasing in altitude. Filter ratio analysis estimates the initial temperature of the cloud in the cavity to be approximately log T ~ 6.25 K with evidence of cooling over time. The subsequent growth of the prominence is accompanied by darkening of the cavity in the 211 Å channel. The observations imply the possibility of prominence formation via in situ condensation of hot plasma from the coronal cavity, in support of the proposed process of magneto-thermal convection in coronal magnetic flux ropes.
Authors: Thomas E. Berger, Wei Liu, and B. C. Low
Projects: SDO-AIA
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Publication Status: Accepted by ApJ Letters, Sept 17, 2012
Last Modified: 2012-09-19 19:22
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