2010/01/19 by Scott W. McIntosh, D. E. Innes, Davina E. Innes +2 · 2 citations
Physics and Astronomy · #Astronomy #Astrophysics #Brightness #Context (archaeology) #Coronal hole #Coronal mass ejection #Geology #Ionosphere and magnetosphere dynamics #Physics #Plasma #Polar #QUIET #Solar and Space Plasma Dynamics #Solar wind #Stellar, planetary, and galactic studies #astro-ph.SR
paper · pdf · doi:10.1051/0004-6361/200913699
published as Astronomy and Astrophysics, 2010, Volume 510, L2 · 4 pages, 4 figures. Accepted to appear in A&A Letters. Movies supporting the Letter can be found in http://download.hao.ucar.edu/pub/mscott/papers/Plumes/
arxiv created 2010/01/19 · openalex publication_date 2010/01/25 · arxiv updated 2010/08/31 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
<i>Context. <i/>Plumes are one of the most ubiquitous features seen at the limb in polar coronal holes and are considered to be a source of high density plasma streams to the fast solar wind.<i>Aims. <i/>We analyze <i>STEREO<i/> observations of plumes and aim to reinterpret and place observations with previous generations of EUV imagers within a new context that was recently developed from <i>Hinode<i/> observations.<i>Methods. <i/>We exploit the higher signal-to-noise, spatial and temporal resolution of the EUVI telescopes over that of <i>SOHO<i/>/EIT to study the temporal variation of polar plumes in high detail. We employ recently developed insight from imaging (and spectral) diagnostics of active region, plage, and quiet Sun plasmas to identify the presence of apparent motions as high-speed upflows in magnetic regions as opposed to previous interpretations of propagating waves.<i>Results. <i/>In almost all polar plumes observed at the limb in these <i>STEREO<i/> sequences, in all coronal passbands, we observe high speed jets of plasma traveling along the structures with a mean velocity of 135 km s<sup>-1<sup/> at a range of temperatures from 0.5–1.5 MK. The jets have an apparent brightness enhancement of ~5% above that of the plumes they travel on and repeat quasi-periodically, with repeat-times ranging from five to twenty-five minutes. We also notice a very weak, fine scale, rapidly evolving, but ubiquitous companion of the plumes that covers the entire coronal hole limb.<i>Conclusions. <i/>The observed jets are remarkably similar in intensity enhancement, periodicity and velocity to those observed in other magnetic regions of the solar atmosphere. They are multi-thermal in nature. We infer that the jets observed on the plumes are a source of heated mass to the fast solar wind. Further, based on the previous results that motivated this study, we suggest that these jets originated in the upper chromosphere.