A5035517300- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Astro and Planetary Science
- Nuclear Physics and Applications
- Particle Detector Development and Performance
- Earthquake Detection and Analysis
- Stellar, planetary, and galactic studies
- Geophysics and Gravity Measurements
- Radiation Therapy and Dosimetry
- Astrophysical Phenomena and Observations
- Solar Radiation and Photovoltaics
- Atomic and Subatomic Physics Research
- Neutrino Physics Research
- Oil, Gas, and Environmental Issues
- Pulsars and Gravitational Waves Research
- Astronomical Observations and Instrumentation
- Particle physics theoretical and experimental studies
- Atmospheric Ozone and Climate
- Statistical and numerical algorithms
- Carbohydrate Chemistry and Synthesis
- Astronomy and Astrophysical Research
- Radiation Detection and Scintillator Technologies
National Defense Academy of Japan
2015-2024
Nagoya University
2003-2023
Universidad Nacional Autónoma de México
2017-2023
The University of Tokyo
2022
National Institute of Science Communication and Information Resources
2022
National Institute for Fusion Science
2022
Chubu University
2017-2021
Indian Space Research Organisation
2018
Aryabhatta Research Institute of Observational Sciences
2018
Inter-University Centre for Astronomy and Astrophysics
2018
Abstract Recently, many superflares on solar-type stars have been discovered as white-light flares (WLFs). The statistical study found a correlation between their energies ( E ) and durations τ ): <?CDATA $\tau \propto {E}^{0.39}$?> , similar to those of solar hard/soft X-ray flares, {E}^{0.2\mbox{--}0.33}$?> . This indicates universal mechanism energy release stellar i.e., magnetic reconnection. We here carried out research 50 WLFs observed with Solar Dynamics Observatory /HMI examined the...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolecular dynamics study of the hydrophobic interaction in an aqueous solution kryptonKyoko Watanabe and Hans C. AndersenCite this: J. Phys. Chem. 1986, 90, 5, 795–802Publication Date (Print):February 1, 1986Publication History Published online1 May 2002Published inissue 1 February 1986https://pubs.acs.org/doi/10.1021/j100277a019https://doi.org/10.1021/j100277a019research-articleACS PublicationsRequest reuse permissionsArticle...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolvent polarization and hydration of the chlorine anionMichiel. Sprik, Michael L. Klein, Kyoko. WatanabeCite this: J. Phys. Chem. 1990, 94, 16, 6483–6488Publication Date (Print):August 1, 1990Publication History Published online1 May 2002Published inissue 1 August 1990https://pubs.acs.org/doi/10.1021/j100379a060https://doi.org/10.1021/j100379a060research-articleACS PublicationsRequest reuse permissionsArticle Views342Altmetric-Citations119LEARN...
We describe a catalogue of solar flares observed by the three instruments (SOT, XRT, EIS) onboard Hinode satellite. From launch satellite in September 2006 until late 2011, about 5000 (larger than A-class GOES classification) occurred during five-year period observations, and more half them were captured telescopes. Observation information for RHESSI Nobeyama Radioheliograph are also included catalogue. This is distributed to users through Internet. It will be useful helpful scientists...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTShape fluctuations in ionic micellesKyoko Watanabe and Michael L. KleinCite this: J. Phys. Chem. 1989, 93, 19, 6897–6901Publication Date (Print):September 1, 1989Publication History Published online1 May 2002Published inissue 1 September 1989https://pubs.acs.org/doi/10.1021/j100356a006https://doi.org/10.1021/j100356a006research-articleACS PublicationsRequest reuse permissionsArticle Views179Altmetric-Citations73LEARN ABOUT THESE METRICSArticle...
The rapid increase in X-ray and extreme ultraviolet (EUV) emissions owing to solar flares enhances ionization the ionosphere, increasing radio wave attenuation. Among these phenomena, shortwave communication disturbance caused by increased electron density ionospheric D region is known as fadeout (SWF). We investigated relationship between SWF's magnitude flare emission, evaluated variation associated with flare. defined minimum frequency (fmin) observed Japan’s ionograms SWF’s magnitude....
Abstract The electron antineutrino flux limits are presented for the brightest gamma-ray burst (GRB) of all time, GRB221009A, over a range 1.8–200 MeV using Kamioka Liquid Scintillator Antineutrino Detector. Using multiple time windows ranging from minutes to days surrounding event search antineutrinos coincident with GRB, we set an upper limit on under assumption several power-law neutrino source spectra, indices 1.5 3 in steps 0.5. No excess was observed any seconds around trigger T 0 ....
An X1.6 flare occurred in AR 12192 on 2014 October 22 at 14:02 UT and was observed by Hinode, IRIS, SDO, RHESSI. We analyze a bright kernel which produces white light (WL) with continuum enhancement hard X-ray (HXR) peak. Taking advantage of the spectroscopic observations IRIS Hinode/EIS, we measure temporal variation plasma properties chromosphere corona. found that explosive evaporation when WL emission occurred, even though intensity hotter lines is quite weak. The correlation emission,...
We report on G-band emission observed by the Solar Optical Telescope onboard Hinode satellite in association with X1.5-class flare 2006 December 14. The enhancements originate from footpoints of flaring coronal magnetic loops, coinciding non-thermal hard X-ray bremsstrahlung sources Reuven Ramaty High Energy Spectroscopic Imager. At available 2 minute cadence, and intensities are furthermore well correlated time. Assuming that continuum a blackbody, we derived total radiative losses...
Solar-C (EUVST) is the next Japanese solar physics mission to be developed with significant contributions from US and European countries. The carries an EUV imaging spectrometer slit-jaw system called EUVST (EUV High-Throughput Spectroscopic Telescope) as payload, take a fundamental step towards answering how plasma universe created evolves Sun influences Earth other planets in our system. In April 2020, ISAS (Institute of Space Astronautical Science) JAXA (Japan Aerospace Exploration...
Kepler Space Telescope and Transiting Exoplanet Survey Satellite unveiled that Sun-like stars frequently host exoplanets. These exoplanets are subject to fluxes of ionizing radiation in the form X-ray extreme-ultraviolet (EUV) may cause changes their atmospheric dynamics chemistry. While can be observed directly, EUV cannot because severe interstellar medium absorption. Here, we present a new empirical method estimate whole stellar XUV (X-ray plus EUV) FUV spectra as function total unsigned...
During the period when Sun was intensely active on October-November 2003, two remarkable solar neutron events were observed by ground-based monitors. On October 28, in association with an X17.2 large flare, neutrons detected high statistical significance (6.4 sigma) monitor at Tsumeb, Namibia. November 4, X28 class relativistic monitors Haleakala Hawaii and Mexico City, telescope Mauna Kea simultaneously. Clear excesses same time these detectors, calculated as 7.5 sigma for Haleakala, 5.2...
Abstract To understand the conditions that produce white-light (WL) enhancements in solar flares, a statistical analysis of visible continuum data as observed by Hinode /Solar Optical Telescope (SOT) was performed. In this study, approximately 100 flare events from M- and X-class flares were selected. The time period during which recorded spans 2011 January to 2016 February. Of these events, half are classified (WLFs), whereas remaining do not show any (non-WLF; NWL). determine existence WL...
Abstract X-rays and extreme ultraviolet (EUV) emissions from solar flares rapidly change the physical composition of Earth’s thermosphere ionosphere, thereby causing space weather phenomena such as communication failures. Numerous empirical models have been developed to estimate effects flare on upper atmosphere. We verified reproduction emission spectra using a one-dimensional hydrodynamic calculation CHIANTI atomic database. To validate proposed model, we used observed EUV obtained by...
Strong signals of neutral emissions were detected in association with a solar flare that occurred on 2005 September 7. They produced by both relativistic ions and electrons. In particular, neutrons observed the neutron telescopes (SNTs) located at Mount Chacaltaya Bolivia Sierra Negra Mexico monitors (NMs) City high statistical significances. At same time, hard X-rays γ-rays, which predominantly emitted high-energy electrons, Geotail INTEGRAL satellites. We found model impulsive emission...
Abstract (±)-N-Benzoyl-cis-2-aminocyclohexanecarboxylic acid has been resolved smoothly by preferential crystallization procedure in the form of its benzylamine salt. A typical run for this presented.
Abstract Solar flares trigger an increase in plasma density the ionosphere including D region, and cause absorption of radio waves, especially high-frequency (HF) ranges, called short-wave fadeout (SWF). To evaluate SWF duration statistically, we analyze long-term (36 years) ionosonde data observed by National Institute Information Communications Technology (NICT). The minimum reflection frequency, f min, is used to detect SWFs from 15-min-resolution observations at Kokubunji, Tokyo, 1981...
The diffuse extragalactic γ-ray background in the MeV region is believed to be due photons from radioactivity produced supernovae throughout history of galaxies universe. In particular, line emission decay chain 56Ni→56Co→56Fe provides dominant photon source (Clayton & Silk). Although iron synthesis occurs all types supernovae, contribution dominated by Type Ia events their higher escape probabilities. Estimates star formation universe suggest a rapid increase factor ~10 present redshift zp...
White-light emissions were observed from an X1.7 class solar flare on 27 January 2012, using three continuum bands (red, green, and blue) of the Solar Optical Telescope (SOT) onboard Hinode satellite. This event occurred near limb, so differences in locations various are consistent with heights above photosphere emission sources. Under this interpretation, our observations white-light occurring at lowest levels where Ca II H occurs. Moreover, centers source regions red, blue wavelengths...
Abstract Shibata and Yokoyama (1999, ApJ, 526, L49; 2002, 577, 422) proposed a method of estimating the coronal magnetic field strength (B) loop length (L) solar stellar flares, on basis magnetohydrodynamic simulations reconnection model. Using scaling law provided by 422), we obtain B L as functions emission measure (EM = n2L3) temperature (T) at flare peak. Here, n is electron density flares. This enables estimation for unresolved flares from observable physical quantities EM T, which...