Browsing by Autor "Tatsumi Koi"

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Detection of Solar Neutrons and Solar Neutron Decay Protons
(2023) Y. Muraki; Tatsumi Koi; Y. Matsubara; S. Masuda; Pedro Miranda; Shoko Miyake; T. Naito; Ernesto Ortiz Fragoso; A. Oshima; T. Sako
Solar flares are broadly classified as impulsive or gradual. Ions accelerated in a gradual flare are thought to be accelerated through a shock acceleration mechanism, but the particle acceleration process in an impulsive flare is still largely unexplored. To understand the acceleration process, it is necessary to measure the high-energy gamma-rays and neutrons produced by the impulsive flare. Under such circumstances, on November 7, 2004, a huge X2.0 flare occurred on the solar surface, where ions were accelerated to energies greater than 10 GeV. The accelerated primary protons collided with the solar atmosphere and produced line gamma-rays and neutrons. These particles were received as neutrons and line gamma-rays, respectively. Neutrons of a few GeV, on the other hand, decay to produce secondary protons while traveling 0.06 au in the solar-terrestrial space. These secondary protons arrived at the magnetopause. Although the flux of secondary protons is very low, the effect of collecting secondary protons arriving in a wide region of the magnetosphere (the Funnel or Horn effect) has resulted in significant signals being received by the solar neutron telescope at Mt. Sierra Negra (4,600 m). This information suggests that ions on the solar surface are accelerated to over 10 GeV with an impulsive flare.
Detection of Solar Neutrons and Solar Neutron Decay Protons
(Multidisciplinary Digital Publishing Institute, 2023) Y. Muraki; Tatsumi Koi; S. Masuda; Y. Matsubara; Pedro Miranda; Shoko Miyake; T. Naito; E. Ortiz; A. Oshima; T. Sako
Solar flares are broadly classified as impulsive or gradual. Ions accelerated in a gradual flare are thought to be accelerated through a shock acceleration mechanism, but the particle acceleration process in an impulsive flare is still largely unexplored. To understand the acceleration process, it is necessary to measure the high-energy gamma rays and neutrons produced by the impulsive flare. Under such circumstances, on 7 November 2004, a huge X2.0 flare occurred on the solar surface, where ions were accelerated to energies greater than 10 GeV. The accelerated primary protons collided with the solar atmosphere and produced line gamma rays and neutrons. These particles were received as neutrons and line gamma rays, respectively. Neutrons of a few GeV, on the other hand, decay to produce secondary protons while traveling 0.06 au in the solar–terrestrial space. These secondary protons arrive at the magnetopause. Although the flux of secondary protons is very low, the effect of collecting secondary protons arriving in a wide region of the magnetosphere (the Funnel or Horn effect) has resulted in significant signals being received by the solar neutron telescope at Mt. Sierra Negra (4600 m). This information suggests that ions on the solar surface are accelerated to over 10 GeV with an impulsive flare.
Solar Neutron Decay Protons Observed in November 7, 2004
(2021) Y. Muraki; Jose F. Valdés Galicia; E. Ortiz; Y. Matsubara; S. Shibata; T. Sako; S. Masuda; Shoko Miyake; M. Tokumaru; Tatsumi Koi
We have found an interesting event registered by the solar neutron telescopes installed at high mountains in Bolivia (5250 m a.s.l.) and Mexico (4600 m a.s.l.). The event was observed on November 7th of 2004 in association with a large solar flare of magnitude X2.0. Some features in the registers reveal the presence of solar neutrons, but also possible solar neutron decay protons (SNDP). SNDPs were recorded on board ISEE3 satellite in June 3rd, 1982 . On October 19th, 1989, the ground level detectors installed in Goose Bay and Deep River revealed the registration of SNDPs. Therefore this is the second example that such an evidence is registered on the Earth’s surface.