Browsing by Autor "K. Watanabe"

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Detection of high-energy solar neutrons and protons by ground level detectors on April 15, 2001
(Elsevier BV, 2008) Y. Muraki; Y. Matsubara; S. Masuda; S. Sakakibara; T. Sako; K. Watanabe; R. Bütikofer; E. O. Flückiger; A. Chilingarian; G. Hovsepyan
EMISIÓN NEUTRÓNICA SOLAR DE LARGA DURACIÓN COMPARADA CON LA RADIACIÓN PRODUCIDA POR ELECTRONES EN LA FULGURACIÓN SOLAR DEL 7 DE SEPTIEMBRE DE 2005
(2007) Takeshi SAKO; K. Watanabe; Y. Muraki; Y. Matsubara; H. Tsujihara; M Yamashita; T. Sakai; S. Shibata; Jose F. Valdés Galicia; L. X. González
T.Sako, K.Watanabe, Y.Muraki, Y.Matsubara, H.Tsujihara, M.Yamashita, T.Sakai, S.Shibata, J.F.Valdes-Galicia, L.X.Gonzalez, A.Hurtado, O.Musalem, P.Miranda, N.Martinic, R.Ticona, A.Velarde, F.Kakimoto, S.Ogio, Y.Tsunesada, H.Tokuno, Y.T.Tanaka, I.Yoshikawa, T.Terasawa, Y.Saito, T.Mukai, y M.Gros 1 Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan. 2 College of Industrial Technologies, Nihon University, 2-11-1 Shinei, Narashino, Chiba 275-0005, Japan. 3 College of Engineering, Chubu University, Kasugai, Aichi 487-8501, Japan. 4 Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Coyoacan DF 04510, Mexico. 5 Instituto de Investigaciones Fisicas, Universidad Mayor de San Andres, La Paz, Bolivia. 6 Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551, Japan. 7 Graduate School of Science, Osaka City University, Osaka 558-8585, Japan. 8 Department of Earth and Planetary Science, University of Tokyo, Tokyo 113-0033, Japan. 9 ISAS/JAXA, Sagamihara 229-8510, Japan. 10 DSM/DAPNIA/SAp, CEA Saclay, 91191 Gif-sur-Yvette, France.
Highly significant detection of solar neutrons on 2005 September 7
(Elsevier BV, 2007) K. Watanabe; T. Sako; Y. Muraki; Y. Matsubara; T. Sakai; S. Shibata; Jose F. Valdés Galicia; L. X. González; A. Hurtado; O. Musalém
Long-lived Solar Neutron Emission in Comparison with Electron-produced Radiation in the 2005 September 7 Solar Flare
(IOP Publishing, 2006) T. Sako; K. Watanabe; Y. Muraki; Y. Matsubara; H. Tsujihara; M. T. Yamashita; T. Sakai; S. Shibata; Jose F. Valdés Galicia; L. X. González
Strong signals of neutral emissions were detected in association with a solar flare that occurred on 2005 September 7. They were produced by both relativistic ions and electrons. In particular, relativistic neutrons were observed with the solar neutron telescopes (SNTs) located at Mount Chacaltaya in Bolivia and Mount Sierra Negra in Mexico and with neutron monitors (NMs) at Chacaltaya and Mexico City with high statistical significances. At the same time, hard X-rays and γ-rays, which were predominantly emitted by high-energy electrons, were detected by the Geotail and the INTEGRAL satellites. We found that a model of the impulsive neutron emission at the time of the X-ray/γ-ray peak can explain the main peaks of all the detected neutron signals, but failed to explain the long tailed decaying phase. An alternative model, in which the neutron emission follows the X-ray/γ-ray profile, also failed to explain the long tail. These results indicate that the acceleration of ions began at the same time as the electrons but that ions were continuously accelerated or trapped longer than the electrons in the emission site. We also demonstrate that the neutron data observed by multienergy channels of SNTs put constraints on the neutron spectrum.
Physics of ion acceleration in the solar flare on 2005 September 7 determines γ-ray and neutron production
(Elsevier BV, 2009) K. Watanabe; R. P. Lin; Säm Krucker; R. J. Murphy; G. H. Share; Mark Harris; M. Gros; Y. Muraki; T. Sako; Y. Matsubara
Solar Neutron Event in Association with a Large Solar Flare on 2000 November 24
(IOP Publishing, 2003) K. Watanabe; Y. Muraki; Y. Matsubara; Kazuaki Murakami; T. Sako; H. Tsuchiya; S. Masuda; M. Yoshimori; N. Ohmori; P. Miranda
Solar neutrons have been detected using the neutron monitor located at Mt. Chacaltaya, Bolivia, in association with a large solar flare on November 24, 2000. This is the first detection of solar neutrons by the neutron monitor that have been reported so far in solar cycle 23. The statistical significance of the detection is 5.5 sigma. In this flare, the intense emission of hard X-rays and gamma-rays has been observed by the Yohkoh Hard X-ray Telescope (HXT) and Gamma Ray Spectrometer (GRS), respectively. The production time of solar neutrons is better correlated with those of hard X-rays and gamma-rays than with the production time of soft X-rays. The observations of the solar neutrons on the ground have been limited to solar flares with soft X-ray class greater than X8 in former solar cycles. In this cycle, however, neutrons were detected associated with an X2.3 solar flare on November 24, 2000. This is the first report of the detection of solar neutrons on the ground associated with a solar flare with its X-ray class smaller than X8.
Solar neutron events in association with large solar flares in November 2003
(Elsevier BV, 2005) K. Watanabe; Y. Muraki; Y. Matsubara; Kazuaki Murakami; T. Sako; P. Miranda; R. Ticona; A. Velarde; F. Kakimoto; S. Ogio