The Sun’s Dynamic Extended Corona Observed in Extreme Ultraviolet. (arXiv:2105.08028v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Seaton_D/0/1/0/all/0/1">Daniel B. Seaton</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hughes_J/0/1/0/all/0/1">J. Marcus Hughes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tadikonda_S/0/1/0/all/0/1">Sivakumara K. Tadikonda</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Caspi_A/0/1/0/all/0/1">Amir Caspi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+DeForest_C/0/1/0/all/0/1">Craig DeForest</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Krimchansky_A/0/1/0/all/0/1">Alexander Krimchansky</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hurlburt_N/0/1/0/all/0/1">Neal E. Hurlburt</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Seguin_R/0/1/0/all/0/1">Ralph Seguin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Slater_G/0/1/0/all/0/1">Gregory Slater</a>
The “middle corona” is a critical transition between the highly disparate
physical regimes of the lower and outer solar corona. Nonetheless, it remains
poorly understood due to the difficulty of observing this faint region (1.5-3
solar radii). New observations from the GOES Solar Ultraviolet Imager in August
and September 2018 provide the first comprehensive look at this region’s
characteristics and long-term evolution in extreme ultraviolet (EUV). Our
analysis shows that the dominant emission mechanism here is resonant scattering
rather than collisional excitation, consistent with recent model predictions.
Our observations highlight that solar wind structures in the heliosphere
originate from complex dynamics manifesting in the middle corona that do not
occur at lower heights. These data emphasize that low-coronal phenomena can be
strongly influenced by inflows from above, not only by photospheric motion, a
factor largely overlooked in current models of coronal evolution. This study
reveals the full kinematic profile of the initiation of several coronal mass
ejections, filling a crucial observational gap that has hindered understanding
of the origins of solar eruptions. These new data uniquely demonstrate how EUV
observations of the middle corona provide strong new constraints on models
seeking to unify the corona and heliosphere.
The “middle corona” is a critical transition between the highly disparate
physical regimes of the lower and outer solar corona. Nonetheless, it remains
poorly understood due to the difficulty of observing this faint region (1.5-3
solar radii). New observations from the GOES Solar Ultraviolet Imager in August
and September 2018 provide the first comprehensive look at this region’s
characteristics and long-term evolution in extreme ultraviolet (EUV). Our
analysis shows that the dominant emission mechanism here is resonant scattering
rather than collisional excitation, consistent with recent model predictions.
Our observations highlight that solar wind structures in the heliosphere
originate from complex dynamics manifesting in the middle corona that do not
occur at lower heights. These data emphasize that low-coronal phenomena can be
strongly influenced by inflows from above, not only by photospheric motion, a
factor largely overlooked in current models of coronal evolution. This study
reveals the full kinematic profile of the initiation of several coronal mass
ejections, filling a crucial observational gap that has hindered understanding
of the origins of solar eruptions. These new data uniquely demonstrate how EUV
observations of the middle corona provide strong new constraints on models
seeking to unify the corona and heliosphere.
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