Author
Saku Tsuneta
Other affiliations: Marshall Space Flight Center, National Institutes of Natural Sciences, Japan, University of Tokyo
Bio: Saku Tsuneta is an academic researcher from Japan Aerospace Exploration Agency. The author has contributed to research in topics: Solar flare & Photosphere. The author has an hindex of 69, co-authored 303 publications receiving 23475 citations. Previous affiliations of Saku Tsuneta include Marshall Space Flight Center & National Institutes of Natural Sciences, Japan.
Topics: Solar flare, Photosphere, Telescope, Nanoflares, Chromosphere
Papers published on a yearly basis
Papers
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TL;DR: The Hinode satellite as discussed by the authors is the successor to the Yohkoh mission, which aims to understand how magnetic energy gets transferred from the photosphere to the upper atmosphere and results in explosive energy releases.
Abstract: The Hinode satellite (formerly Solar-B) of the Japan Aerospace Exploration Agency’s Institute of Space and Astronautical Science (ISAS/JAXA) was successfully launched in September 2006. As the successor to the Yohkoh mission, it aims to understand how magnetic energy gets transferred from the photosphere to the upper atmosphere and results in explosive energy releases. Hinode is an observatory style mission, with all the instruments being designed and built to work together to address the science aims. There are three instruments onboard: the Solar Optical Telescope (SOT), the EUV Imaging Spectrometer (EIS), and the X-Ray Telescope (XRT). This paper provides an overview of the mission, detailing the satellite, the scientific payload, and operations. It will conclude with discussions on how the international science community can participate in the analysis of the mission data.
1,904 citations
TL;DR: The solar optical telescope (SOT) as discussed by the authors is a 50-cm diffraction-limited Gregorian telescope with the Stokes Spectro-Polarimeter (SP) attached to it.
Abstract: The Solar Optical Telescope (SOT) aboard the Hinode satellite (formerly called Solar-B) consists of the Optical Telescope Assembly (OTA) and the Focal Plane Package (FPP). The OTA is a 50-cm diffraction-limited Gregorian telescope, and the FPP includes the narrowband filtergraph (NFI) and the broadband filtergraph (BFI), plus the Stokes Spectro-Polarimeter (SP). The SOT provides unprecedented high-resolution photometric and vector magnetic images of the photosphere and chromosphere with a very stable point spread function and is equipped with an image-stabilization system with performance better than 0.01 arcsec rms. Together with the other two instruments on Hinode (the X-Ray Telescope (XRT) and the EUV Imaging Spectrometer (EIS)), the SOT is poised to address many fundamental questions about solar magnetohydrodynamics. This paper provides an overview; the details of the instrument are presented in a series of companion papers.
1,448 citations
TL;DR: The Solar Optical Telescope (SOT) as mentioned in this paper is a 50 cm diffraction-limited Gregorian telescope, and includes the narrow-band (NFI) and wideband (BFI) filtergraphs.
Abstract: The Solar Optical Telescope (SOT) aboard the Hinode satellite (formerly called Solar-B) consists of the Optical Telescope Assembly (OTA) and the Focal Plane Package (FPP). The OTA is a 50 cm diffraction-limited Gregorian telescope, and the FPP includes the narrow-band (NFI) and wide-band (BFI) filtergraphs, plus the Stokes spectro-polarimeter (SP). SOT provides unprecedented high resolution photometric and vector magnetic images of the photosphere and chromosphere with a very stable point spread function, and is equipped with an image stabilization system that reduces the error to less than 0.01 arcsec rms. Together with the other two instruments on Hinode (the X-Ray Telescope (XRT) and EUV Imaging Spectrometer (EIS)), SOT is poised to address many fundamental questions about solar magneto-hydrodynamics. Note that this is an overview, and the details of the instrument are presented in a series of companion papers.
1,229 citations
TL;DR: In this paper, the authors identify the reconnection region as the site of particle acceleration, suggesting that the basic physics of the magnetic reconnection process may be common to both types of flares.
Abstract: SOLAR flares are thought to be the result of magnetic reconnection — the merging of antiparallel magnetic fields and the consequent release of magnetic energy. Flares are classified into two types1: compact and two-ribbon. The two-ribbon flares, which appear as slowly-developing, long-lived large loops, are understood theoretically2–6 as arising from an eruption of a solar prominence that pulls magnetic field lines upward into the corona. As the field lines form an inverted Y-shaped structure and relax, the reconnection of the field lines takes place. This view has been supported by recent observations7–10. A different mechanism seemed to be required, however, to produce the short-lived, impulsive compact flares. Here we report observations made with the Yohkoh11 Hard X-ray Telescope12 and Soft X-ray Telescope13, which show a compact flare with a geometry similar to that of a two-ribbon flare. We identify the reconnection region as the site of particle acceleration, suggesting that the basic physics of the reconnection process (which remains uncertain) may be common to both types of flare.
1,121 citations
TL;DR: The Soft X-ray Telescope (SXT) of the SOLAR-A mission is designed to produce images of solar flares with excellent angular and time resolution as well as full-disk images for general studies.
Abstract: The Soft X-ray Telescope (SXT) of the SOLAR-A mission is designed to produce X-ray movies of flares with excellent angular and time resolution as well as full-disk X-ray images for general studies. A selection of thin metal filters provide a measure of temperature discrimination and aid in obtaining the wide dynamic range required for solar observing. The co-aligned SXT aspect telescope will yield optical images for aspect reference, white-light flare and sunspot studies, and, possibly, helioseismology. This paper describes the capabilities and characteristics of the SXT for scientific observing.
1,009 citations
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TL;DR: The Atmospheric Imaging Assembly (AIA) as discussed by the authors provides multiple simultaneous high-resolution full-disk images of the corona and transition region up to 0.5 R ⊙ above the solar limb with 1.5-arcsec spatial resolution and 12-second temporal resolution.
Abstract: The Atmospheric Imaging Assembly (AIA) provides multiple simultaneous high-resolution full-disk images of the corona and transition region up to 0.5 R ⊙ above the solar limb with 1.5-arcsec spatial resolution and 12-second temporal resolution. The AIA consists of four telescopes that employ normal-incidence, multilayer-coated optics to provide narrow-band imaging of seven extreme ultraviolet (EUV) band passes centered on specific lines: Fe xviii (94 A), Fe viii, xxi (131 A), Fe ix (171 A), Fe xii, xxiv (193 A), Fe xiv (211 A), He ii (304 A), and Fe xvi (335 A). One telescope observes C iv (near 1600 A) and the nearby continuum (1700 A) and has a filter that observes in the visible to enable coalignment with images from other telescopes. The temperature diagnostics of the EUV emissions cover the range from 6×104 K to 2×107 K. The AIA was launched as a part of NASA’s Solar Dynamics Observatory (SDO) mission on 11 February 2010. AIA will advance our understanding of the mechanisms of solar variability and of how the Sun’s energy is stored and released into the heliosphere and geospace.
4,321 citations
TL;DR: The Hinode satellite as discussed by the authors is the successor to the Yohkoh mission, which aims to understand how magnetic energy gets transferred from the photosphere to the upper atmosphere and results in explosive energy releases.
Abstract: The Hinode satellite (formerly Solar-B) of the Japan Aerospace Exploration Agency’s Institute of Space and Astronautical Science (ISAS/JAXA) was successfully launched in September 2006. As the successor to the Yohkoh mission, it aims to understand how magnetic energy gets transferred from the photosphere to the upper atmosphere and results in explosive energy releases. Hinode is an observatory style mission, with all the instruments being designed and built to work together to address the science aims. There are three instruments onboard: the Solar Optical Telescope (SOT), the EUV Imaging Spectrometer (EIS), and the X-Ray Telescope (XRT). This paper provides an overview of the mission, detailing the satellite, the scientific payload, and operations. It will conclude with discussions on how the international science community can participate in the analysis of the mission data.
1,904 citations
TL;DR: The Extreme-ultraviolet Imaging Telescope (EIT) as discussed by the authors provides wide-field images of the corona and transition region on the solar disc and up to 1.5 R⊙ above the solar limb.
Abstract: The Extreme-ultraviolet Imaging Telescope (EIT) will provide wide-field images of the corona and transition region on the solar disc and up to 1.5 R⊙ above the solar limb. Its normal incidence multilayer-coated optics will select spectral emission lines from Fe IX (171 A), Fe XII (195 A), Fe XV (284 A), and He II (304 A) to provide sensitive temperature diagnostics in the range from 6 × 104 K to 3 × 10 6 K. The telescope has a 45×45 arcmin field of view and 2.6 arcsec pixels which will provide approximately 5-arcsec spatial resolution. The EIT will probe the coronal plasma on a global scale, as well as the underlying cooler and turbulent atmosphere, providing the basis for comparative analyses with observations from both the ground and other SOHO instruments. This paper presents details of the EIT instrumentation, its performance and operating modes.
1,856 citations
TL;DR: The solar optical telescope (SOT) as discussed by the authors is a 50-cm diffraction-limited Gregorian telescope with the Stokes Spectro-Polarimeter (SP) attached to it.
Abstract: The Solar Optical Telescope (SOT) aboard the Hinode satellite (formerly called Solar-B) consists of the Optical Telescope Assembly (OTA) and the Focal Plane Package (FPP). The OTA is a 50-cm diffraction-limited Gregorian telescope, and the FPP includes the narrowband filtergraph (NFI) and the broadband filtergraph (BFI), plus the Stokes Spectro-Polarimeter (SP). The SOT provides unprecedented high-resolution photometric and vector magnetic images of the photosphere and chromosphere with a very stable point spread function and is equipped with an image-stabilization system with performance better than 0.01 arcsec rms. Together with the other two instruments on Hinode (the X-Ray Telescope (XRT) and the EUV Imaging Spectrometer (EIS)), the SOT is poised to address many fundamental questions about solar magnetohydrodynamics. This paper provides an overview; the details of the instrument are presented in a series of companion papers.
1,448 citations
TL;DR: The Interface Region Imaging Spectrograph (IRIS) as mentioned in this paper provides simultaneous spectra and images of the photosphere, chromosphere, transition region, and corona with 0.33 arcsec and up.
Abstract: The Interface Region Imaging Spectrograph (IRIS) small explorer spacecraft provides simultaneous spectra and images of the photosphere, chromosphere, transition region, and corona with 0.33 – 0.4 arcsec spatial resolution, two-second temporal resolution, and 1 km s−1 velocity resolution over a field-of-view of up to 175 arcsec × 175 arcsec. IRIS was launched into a Sun-synchronous orbit on 27 June 2013 using a Pegasus-XL rocket and consists of a 19-cm UV telescope that feeds a slit-based dual-bandpass imaging spectrograph. IRIS obtains spectra in passbands from 1332 – 1358 A, 1389 – 1407 A, and 2783 – 2834 A, including bright spectral lines formed in the chromosphere (Mg ii h 2803 A and Mg ii k 2796 A) and transition region (C ii 1334/1335 A and Si iv 1394/1403 A). Slit-jaw images in four different passbands (C ii 1330, Si iv 1400, Mg ii k 2796, and Mg ii wing 2830 A) can be taken simultaneously with spectral rasters that sample regions up to 130 arcsec × 175 arcsec at a variety of spatial samplings (from 0.33 arcsec and up). IRIS is sensitive to emission from plasma at temperatures between 5000 K and 10 MK and will advance our understanding of the flow of mass and energy through an interface region, formed by the chromosphere and transition region, between the photosphere and corona. This highly structured and dynamic region not only acts as the conduit of all mass and energy feeding into the corona and solar wind, it also requires an order of magnitude more energy to heat than the corona and solar wind combined. The IRIS investigation includes a strong numerical modeling component based on advanced radiative–MHD codes to facilitate interpretation of observations of this complex region. Approximately eight Gbytes of data (after compression) are acquired by IRIS each day and made available for unrestricted use within a few days of the observation.
1,238 citations