Browsing by Author "Ishitsuka, Mutsumi"

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    "Dandelion" filament eruption and coronal waves associated with a solar flare on 2011 February 16
    (IOP Publishing, 2017-01) Cabezas, Denis P.; Martínez, Lurdes M.; Buleje, Yovanny J.; Ishitsuka, Mutsumi; Ishitsuka, José K.; Morita, Satoshi; Asai, Ayumi; Ueno, Satoru; Ishii, Takato T.; Kitai, Reizaburo; Takasao, Shinsuke; Yoshinaga, Yusuke; Otsuji, Kenichi; Shibata, Kazunari
    Coronal disturbances associated with solar flares, such as Hα Moreton waves, X-ray waves, and extreme ultraviolet (EUV) coronal waves, are discussed herein in relation to magnetohydrodynamic fast-mode waves or shocks in the corona. To understand the mechanism of coronal disturbances, full-disk solar observations with high spatial and temporal resolution over multiple wavelengths are of crucial importance. We observed a filament eruption, whose shape is like a “dandelion,” associated with the M1.6 flare that occurred on 2011 February 16 in Hα images taken by the Flare Monitoring Telescope at Ica University, Peru. We derive the three-dimensional velocity field of the erupting filament. We also identify winking filaments that are located far from the flare site in the Hα images, whereas no Moreton wave is observed. By comparing the temporal evolution of the winking filaments with those of the coronal wave seen in the EUV images data taken by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory and by the Extreme Ultraviolet Imager on board the Solar Terrestrial Relations Observatory-Ahead, we confirm that the winking filaments were activated by the EUV coronal wave.
    Palabras clave:AstrophysicsHeliosphereSolar chromosphere
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    Estimating daytime vertical ExB drift velocities in the equatorial F‐region using ground‐based magnetometer observations
    (American Geophysical Union, 2002-06-28) Anderson, David; Anghel, Adela; Yumoto, Kiyohumi; Ishitsuka, Mutsumi; Kudeki, Erhan
    The daytime equatorial electrojet is a narrow band of enhanced eastward current flowing in the 100 to 120 km altitude region within ±2° latitude of the dip equator. A unique way of determining the daytime strength of the electrojet is to observe the difference in the magnitudes of the Horizontal (H) component between a magnetometer placed directly on the magnetic equator and one displaced 6 to 9 degrees away. The difference between these measured H values provides a direct measure of the daytime electrojet current, and in turn, the magnitude of the vertical ExB drift velocity in the F region ionosphere. This paper discusses a recent study that has established the quantitative relationship between the vertical ExB drift velocity in the ionospheric F region and the daytime strength of the equatorial electrojet in the South American (west coast) longitude sector.
    Palabras clave:ElectrojetF regionGround-based measurement