Browsing by Autor "T. Koi"

Now showing 1 - 3 of 3

Proton penetration efficiency over a high altitude observatory in Mexico
(SciPost.org, 2023) Shoko Miyake; T. Koi; Y. Muraki; Y. Matsubara; S. Masuda; P. Miranda; T. Naito; E. Ortiz; A. Oshima; T. Sakai
In association with a large solar flare on November 7, 2004, the solar neutron detectors located at Mt. Chacaltaya (5,250 m) in Bolivia and Mt. Sierra Negra (4,600 m) in Mexico recorded very interesting events. In order to explain these events, we have performed a calculation solving the equation of motion of anti-protons inside the magnetosphere. Based on these results, the Mt. Chacaltaya event may be explained by the detection of solar neutrons, while the Mt. Sierra Negra event may be explained by the first detection of very high energy solar neutron decay protons (SNDPs) around 6 GeV.
Proton Penetration Efficiency over Sierra Negra (Mexico) and Oulu (Finland)
(2023) Y. Muraki; Shoko Miyake; T. Koi; Y. Matsubara; S. Masuda; P. Miranda; T. Naito; E. Ortiz; A. Oshima; T. Sako
On November 7, 2004, a large solar flare was observed, which had a notable impact on the solar neutron detectors located at Mt. Chacaltaya (5,250 m) in Bolivia and Mt. Sierra Negra (4,600 m) in Mexico. In addition, the neutron monitor at Oulu, Finland, recorded a 5-sigma enhancement. In order to determine the causes of these enhancements, we performed trajectory simulations ejecting anti-protons from 20 km above each location, and checked whether or not these anti-protons could reach the magnetopause (∼8𝑅E). Then, we understand that the Chacaltaya enhancement was caused by solar neutrons themselves, while the Mt. Sierra Negra event may have been produced by high-energy solar neutron decay protons (SNDPs) with energies ≥ 6 GeV. Based on our anti- proton trajectory analysis, we suggest that the enhancement at Oulu may also have been produced by solar neutron decay protons with energies around ≥ 200 MeV. During this flare, protons were accelerated up to 10 GeV within one minute, leading to the production of SNDPs.
Report on scipost_202207_00031v1
(2022) Shoko Miyake; T. Koi; Y. Muraki; Y. Matsubara; S. Masuda; Pedro Miranda; T. Naito; E. Ortiz; A. Oshima; T. Sakai
In association with a large solar flare on November 7, 2004, the solar neutron detectors located at Mt. Chacaltaya (5,250 m) in Bolivia and Mt.Sierra Negra (4,600 m) in Mexico recorded very interesting events.In order to explain these events, we have performed a calculation solving the equation of motion of anti-protons inside the magnetosphere.Based on these results, the Mt.Chacaltaya event may be explained by the detection of solar neutrons, while the Mt.Sierra Negra event may be explained by the first detection of very high energy solar neutron decay protons (SNDPs) around 6 GeV.