Search Publications
Solar horizontal flow evaluation using neural network and numerical simulations with snapshot data
Katsukawa, Yukio; Ishikawa, Ryohtaroh T.; Masaki, Hiroyuki +1 more
We suggest a method that evaluates the horizontal velocity in the solar photosphere with easily observable values using a combination of neural network and radiative magnetohydrodynamics simulations. All three-component velocities of thermal convection on the solar surface have important roles in generating waves in the upper atmosphere. However, …
Investigating the magnetic field of the quiet Sun internetwork
Ichimoto, Kiyoshi; Deng, Yuanyong; Shaltout, Abdelrazek M. K. +1 more
We analyze the magnetism of the quiet Sun internetwork (IN) using high-spatial-resolution data obtained by the spectropolarimeter (SP) of the Solar Optical Telescope aboard the Hinode satellite near the disk center of the Sun. The SP data were inverted using the Stokes Inversion based on Response functions (SIR) inversion code with a single-compon…
Achievements of Hinode in the first eleven years
Solanki, Sami K.; Tiwari, Sanjiv K.; Reeves, Katharine K. +33 more
Hinode is Japan's third solar mission following Hinotori (1981-1982) and Yohkoh (1991-2001): it was launched on 2006 September 22 and is in operation currently. Hinode carries three instruments: the Solar Optical Telescope, the X-Ray Telescope, and the EUV Imaging Spectrometer. These instruments were built under international collaboration with th…
Observations of photospheric magnetic structure below a dark filament using the Hinode Spectro-Polarimeter
Shimojo, Masumi; Yokoyama, Takaaki; Katsukawa, Yukio
The structure of the photospheric vector magnetic field below a dark filament on the Sun is studied using the observations of the Spectro-Polarimeter attached to the Solar Optical Telescope onboard Hinode. Special attention is paid to discriminating between two suggested models, a flux rope or a bent arcade. "Inverse polarity" orientation is possi…
Observational study on the fine structure and dynamics of a solar jet. II. Energy release process revealed by spectral analysis
Shibata, Kazunari; Ichimoto, Kiyoshi; Ueno, Satoru +3 more
We report on a solar jet phenomenon associated with the C5.4 class flare on 2014 November 11. The data of the jet was provided by the Solar Dynamics Observatory, the X-Ray Telescope (XRT) aboard Hinode, and the Interface Region Imaging Spectrograph and Domeless Solar Telescope (DST) at Hida Observatory, Kyoto University. These plentiful data enabl…
Does the radial-tangential macroturbulence model adequately describe the spectral line broadening of solar-type stars?*
Takeda, Yoichi; UeNo, Satoru
In incorporating the effect of atmospheric turbulence in the broadening of spectral lines, the so-called radial-tangential macroturbulence (RTM) model has been widely used in the field of solar-type stars, which was devised from intuitive appearance of the granular velocity field of the Sun. Since this model assumes that turbulent motions are rest…
Validation of a scaling law for the coronal magnetic field strength and loop length of solar and stellar flares
Namekata, Kosuke; Shibata, Kazunari; Watanabe, Kyoko +2 more
Shibata and Yokoyama (1999, ApJ, 526, L49; 2002, ApJ, 577, 422) proposed a method of estimating the coronal magnetic field strength (B) and magnetic loop length (L) of solar and stellar flares, on the basis of magnetohydrodynamic simulations of the magnetic reconnection model. Using the scaling law provided by Shibata and Yokoyama (1999, ApJ, 526,…
A study of the long term evolution in active region upflows
Harra, Louise K.; Ugarte-Urra, Ignacio; Baker, Deborah +5 more
Since their discovery, upflows at the edges of active regions have attracted a lot of interest, primarily as they could potentially contribute to the slow solar wind. One aspect that has not been studied yet is how the long term evolution of active regions impacts the upflows. In this work, we analyze one active region that survives three solar ro…
Observational study on the fine structure and dynamics of a solar jet. I. Energy build-up process around a satellite spot
Shibata, Kazunari; Ichimoto, Kiyoshi; Ueno, Satoru +3 more
We report on a solar jet phenomenon associated with successive flares on 2014 November 10. These explosive events were involved with the satellite spots' emergence around a δ-type sunspot in the decaying active region NOAA 12205. The data for this jet were provided by the Solar Dynamics Observatory, the X-Ray Telescope aboard Hinode, and the Inter…
Temporal relations between magnetic bright points and the solar sunspot cycle
Van Doorsselaere, Tom; Utz, Dominik; Muller, Richard
The Sun shows a global magnetic field cycle traditionally best visible in the photosphere as a changing sunspot cycle featuring roughly an 11-year period. In addition we know that our host star also harbours small-scale magnetic fields often seen as strong concentrations of magnetic flux reaching kG field strengths. These features are situated in …