19 research outputs found
Observational Signatures of Magnetic Reconnection in the Extended Corona and First Results from the Hi-C II Sounding Rocket
No abstract availabl
Defining the Middle Corona
International audienceAbstract The middle corona, the region roughly spanning heliocentric distances from 1.5 to 6 solar radii, encompasses almost all of the influential physical transitions and processes that govern the behavior of coronal outflow into the heliosphere. The solar wind, eruptions, and flows pass through the region, and they are shaped by it. Importantly, the region also modulates inflow from above that can drive dynamic changes at lower heights in the inner corona. Consequently, the middle corona is essential for comprehensively connecting the corona to the heliosphere and for developing corresponding global models. Nonetheless, because it is challenging to observe, the region has been poorly studied by both major solar remote-sensing and in-situ missions and instruments, extending back to the Solar and Heliospheric Observatory (SOHO) era. Thanks to recent advances in instrumentation, observational processing techniques, and a realization of the importance of the region, interest in the middle corona has increased. Although the region cannot be intrinsically separated from other regions of the solar atmosphere, there has emerged a need to define the region in terms of its location and extension in the solar atmosphere, its composition, the physical transitions that it covers, and the underlying physics believed to shape the region. This article aims to define the middle corona, its physical characteristics, and give an overview of the processes that occur there
Routes beyond compulsory schooling
England and Wales Youth Cohort StudySIGLEAvailable from British Library Document Supply Centre- DSC:9421.5305(DE-YCR--31) / BLDSC - British Library Document Supply CentreGBUnited Kingdo
Quantification of 31 volatile organic compounds in whole blood using solid-phase microextraction and gas chromatography–mass spectrometry☆
The determination of organophosphonate nerve agent metabolites in human urine by hydrophilic interaction liquid chromatography tandem mass spectrometry
Defining the Middle Corona
The middle corona, the region roughly spanning heliocentric distances from 1.5 to 6 solar radii, encompasses almost all of the influential physical transitions and processes that govern the behavior of coronal outflow into the heliosphere. The solar wind, eruptions, and flows pass through the region, and they are shaped by it. Importantly, the region also modulates inflow from above that can drive dynamic changes at lower heights in the inner corona. Consequently, the middle corona is essential for comprehensively connecting the corona to the heliosphere and for developing corresponding global models. Nonetheless, because it is challenging to observe, the region has been poorly studied by both major solar remote-sensing and in-situ missions and instruments, extending back to the Solar and Heliospheric Observatory (SOHO) era. Thanks to recent advances in instrumentation, observational processing techniques, and a realization of the importance of the region, interest in the middle corona has increased. Although the region cannot be intrinsically separated from other regions of the solar atmosphere, there has emerged a need to define the region in terms of its location and extension in the solar atmosphere, its composition, the physical transitions that it covers, and the underlying physics believed to shape the region. This article aims to define the middle corona, its physical characteristics, and give an overview of the processes that occur there.ISSN:0038-0938ISSN:1573-093
Quiet Sun Center to Limb Variation of the Linear Polarization Observed by CLASP2 Across the Mg II h & k Lines
The CLASP2 (Chromospheric LAyer SpectroPolarimeter 2) sounding rocket mission
was launched on 2019 April 11. CLASP2 measured the four Stokes parameters of
the Mg II h & k spectral region around 2800 Angstroms along a 200 arcsecond
slit at three locations on the solar disk, achieving the first spatially and
spectrally resolved observations of the solar polarization in this near
ultraviolet region. The focus of the work presented here is the center-to-limb
variation of the linear polarization across these resonance lines, which is
produced by the scattering of anisotropic radiation in the solar atmosphere.
The linear polarization signals of the Mg II h & k lines are sensitive to the
magnetic field from the low to the upper chromosphere through the Hanle and
magneto-optical effects. We compare the observations to theoretical predictions
from radiative transfer calculations in unmagnetized semi-empirical models,
arguing that magnetic fields and horizontal inhomogeneities are needed to
explain the observed polarization signals and spatial variations. This
comparison is an important step in both validating and refining our
understanding of the physical origin of these polarization signatures, and also
in paving the way toward future space telescopes for probing the magnetic
fields of the solar upper atmosphere via ultraviolet spectropolarimetry.Comment: 14 pages, 5 figures, to be published in the Astrophysical Journal
(ApJ), initially submitted May 2022, revised submission July 202