Hinode, IRIS, and ATERUI Cooperate on 70 year old Solar Mystery
Solar
physicists have captured the first direct observational signatures of
resonant absorption, thought to play an important role in solving the
“coronal heating problem” which has defied explanation for over 70
years.
Figure: (Left) For reference, an image of the entire Sun taken by SDO/AIA in extreme ultra-violet light (false color
). (Right) An image of a solar prominence at the limb of the Sun taken by Hinode/SOT in visible light (Ca II H line, false color). As
shown in the image, a prominence is composed of long, thin structures
called threads. A scale model of the Earth is shown on the right for
reference.
An international research team from
Japan, the U.S.A., and Europe led by Drs. Joten Okamoto and Patrick
Antolin combined high resolution observations from JAXA’s Hinode mission
and NASA’s IRIS (Interface Region Imaging Spectrograph) mission,
together with state-of-the-art numerical simulations and modeling from
NAOJ’s ATERUI supercomputer. In the combined data, they were able to
detect and identify the observational signatures of resonant absorption.
Resonant absorption is a process where
two different types of magnetically driven waves resonate, strengthening
one of them. In particular this research looked at a type of magnetic
waves known as Alfvénic waves which can propagate through a prominence
(a filamentary structure of cool, dense gas floating in thecorona).
Here, for the first time, researchers were able to directly observe
resonant absorption between transverse waves and torsional waves,
leading to a turbulent flow which heats the prominence. Hinode observed
the transverse motion and IRIS observed the torsional motion; these
results would not have been possible without both satellites.
This new information can help explain how
the solar corona reaches temperatures of 1,000,000 degrees Celsius; the
so called “coronal heating problem.”
- provided by ⇒ NAOJ
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