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010105:
Motions of coronal-hole boundaries I. Supergranulation
In this nugget, we expected to find that the boundaries of the coronal
hole would flutter like a Kansas curtain in a thunderstorm, as a
consequence of the solar surface motions we call supergranulation.
On first look, that may not be the case.
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010112:
"Starburst" Images and Scattering Research
This week the SXT scientists are gathered for
a small workshop dedicated to the subject of this
nugget, which is another of our series on how the SXT instrument
works. We have to understand all the nitty-gritty details of the
instrument before we can be confident about what is real, and what is not,
in our data.
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010119:
A Flare in an Almost-Anemone
When a solar active region emerges in a coronal hole,
the new active region may not appear to have any
coronal connections to other regions.
We call this an "anemone" region, after the
windflower. It's noteworthy that the tiny little flare that
occurred in this region is more than twice the diameter of Earth!
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010126:
A coronal conveyor belt?
Normally we write these Yohkoh science nuggets based on
interesting phenomena that we spot for the first time in the SXT data. Sometimes we miss something, and
in this case, it's what the authors of a published paper describe as
the conveyance of energy from one solar active region to another.
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010202:
A dark 'S' erupted!
Bright 'S' shapes (sigmoids) are popular among solar physicists,
especially those who study flares and CMEs.
However, the 'S' here is invisible to SXT.
A gorgeous dark 'S' shape appeared in SoHO/EIT images
and produced a spectacular Coronal Mass Ejection.
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010209:
A most peculiar high-energy event
Normally we write these Yohkoh science nuggets mostly about
coronal soft X-ray sources.
In this Nugget we talk about events that emit hard X-rays, gamma-rays, and
copious "solar cosmic rays" -- which make the topics that are our bread
and butter seem rather flacid.
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010216:
A two-sided jet 1,000,000 km long
Soft X-ray "jets" were one of the truly new discoveries of
Yohkoh/SXT, apparently one that was not anticipated by the
NASA Skylab mission 30 years ago.
Here we report a huge bi-directional jet that spread out across
the solar surface, with a beautiful structure.
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010223:
Two-stage dimming
Coronal dimming, seen in soft X-rays, should rightly be regarded as one
of Yohkoh's major discoveries.
This is one of those cases where a coronal disturbance
does not focus entirely down to a compact origin (eg a major impulsive
flare); instead, there are distinctly global effects.
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010302:
Temperature of active region loops
In order to understand how the solar corona is heated, the distribution
of temperature along a typical X-ray loop is essential information.
To get this, you take the ratio of
two images in different filters (with slightly different temperature
sensitivities), and the ratio directly gives you a temperature.
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