Bibcode
Kano, Ryouhei; Ishikawa, Ryohko; McKenzie, David Eugene; Trujillo Bueno, Javier; Song, Donguk; Yoshida, Masaki; Okamoto, Takenori; Rachmeler, Laurel; Kobayashi, Ken; Auchere, Frederic
Referencia bibliográfica
American Astronomical Society Meeting #234, id. 302.16. Bulletin of the American Astronomical Society, Vol. 51, No. 4
Advertised on:
6
2019
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Descripción
Ultraviolet polarimetry offers a unique opportunity to explore the upper
solar chromosphere and the transition region (TR) to the million-degree
corona. These outer atmospheric regions play a key role in the transfer
of mass and energy from the solar photosphere to the corona. With a
sounding rocket experiment called the Chromospheric Lyman-Alpha
Spectro-Polarimeter (CLASP), in September 2015 we succeeded in obtaining
the first measurement of the linear polarization produced by scattering
processes in the hydrogen Lyman-α line of the solar disk
radiation. The analysis and interpretation of such spectro-polarimetric
observation allowed us to obtain information on the geometrical
complexity of the corrugated surface that delineates the TR, as well as
on the magnetic field strength via the Hanle effect. At the same time,
the CLASP slit-jaw (SJ) optics system, which is a Lyman-α filter
imager characterized by a FWHM= 7 nm, allowed us to obtain broad-band
Stokes-I and Q/I images over a large field of view. The obtained
broad-band Q/I images are dominated by the scattering polarization
signals of the Lyman-α wings, and not by the much weaker
line-center signals where the Hanle effect operates. Recently, Alsina
Ballester et al. (2019, ApJ, in press) showed that the scattering
polarization signals of the Lyman-α wings are sensitive to
chromospheric magnetic fields via the magneto-optical effects.
Therefore, Lyman-α imaging polarimetry is of scientific interest
also for magnetic-field investigations. On April 11, 2019, we performed
another sounding rocket experiment, called the Chromospheric LAyer
Spectro-Polarimeter (CLASP2). We used the same instrument after
significant modifications in order to obtain spectro-polarimetric
observations of a plage and a quiet region in the ionized magnesium
lines around 280 nm (i.e., the Mg II h & k lines). At the same time,
the CLASP2 SJ optics system allowed us to obtain broad-band Q/I and U/I
images at the Lyman-α wavelength, in addition to the well-known SJ
intensity images. In this presentation, we provide a first overview of
the CLASP2 SJ data.