Showing papers by "Akira Kadokura published in 2021"
15 citations
TL;DR: In this paper, the authors show that the muon and neutron data are consistent with those from other locations by comparing intensity variations during a space weather event, which is expected from the atmospheric temperature effect.
Abstract: Muon detectors and neutron monitors were recently installed at Syowa Station, in the Antarctic, to observe different types of secondary particles resulting from cosmic ray interactions simultaneously from the same location. Continuing observations will give new insight into the response of muon detectors to atmospheric and geomagnetic effects. Operation began in February, 2018 and the system has been stable with a duty-cycle exceeding 94%. Muon data shows a clear seasonal variation, which is expected from the atmospheric temperature effect. We verified successful operation by showing that the muon and neutron data are consistent with those from other locations by comparing intensity variations during a space weather event. We have established a web page to make real time data available with interactive graphics (http://polaris.nipr.ac.jp/cosmicrays/).
8 citations
7 citations
6 citations
Shinshu University1, National Institute of Polar Research2, Japan Aerospace Exploration Agency3, Chiba University4, Nagoya University5, National Institute for Space Research6, George Mason University7, Kuwait University8, University of Tasmania9, University of Delaware10, The Public Authority for Applied Education and Training11, University of Arizona12
TL;DR: In this article, the authors demonstrate that global observations of high-energy cosmic rays contribute to understanding unique characteristics of a large-scale magnetic flux rope causing a magnetic storm in August 2018.
Abstract: We demonstrate that global observations of high-energy cosmic rays contribute to understanding unique characteristics of a large-scale magnetic flux rope causing a magnetic storm in August 2018. Following a weak interplanetary shock on August 25, 2018, a magnetic flux rope caused an unexpectedly large geomagnetic storm. It is likely that this event became geoeffective because the flux rope was accompanied by a corotating interaction region and compressed by high-speed solar wind following the flux rope. In fact, a Forbush decrease was observed in cosmic-ray data inside the flux rope as expected, and a significant cosmic-ray density increase exceeding the unmodulated level before the shock was also observed near the trailing edge of the flux rope. The cosmic-ray density increase can be interpreted in terms of the adiabatic heating of cosmic rays near the trailing edge of the flux rope, as the corotating interaction region prevents free expansion of the flux rope and results in the compression near the trailing edge. A northeast-directed spatial gradient in the cosmic-ray density was also derived during the cosmic-ray density increase, suggesting that the center of the heating near the trailing edge is located northeast of Earth. This is one of the best examples demonstrating that the observation of high-energy cosmic rays provides us with information that can only be derived from the cosmic ray measurements to observationally constrain the three-dimensional macroscopic picture of the interaction between coronal mass ejections and the ambient solar wind, which is essential for prediction of large magnetic storms.
6 citations
Korea Astronomy and Space Science Institute1, Korea University of Science and Technology2, National Cheng Kung University3, Nagoya University4, National Institute of Polar Research5, University of Tokyo6, Academia Sinica Institute of Astronomy and Astrophysics7, Kyoto University8, Kanazawa University9, Kyushu Institute of Technology10, Japan Aerospace Exploration Agency11, Osaka University12, Tohoku University13
5 citations
TL;DR: In this paper, the electric field surrounding the conductive sensor unit of an electric field mill was estimated using a three-dimensional Poisson equation, and the results are applicable to studies on dust storm electrification on Mars' and Earth's deserts, snowstorm electrification in the polar regions, and high mountains such as Mt. Fuji in Japan, and turbulent electrification for industrial dust, which provides the identification of intense electrification and storms.
3 citations
2 citations
TL;DR: In this article, the author's proof corrections were not correctly taken into account, due to confusion in the proof correction process, and the corrections are listed below, highlighted by a boldface font.
Abstract: Due to confusion in the proof correction process, the author’s proof corrections were not correctly taken into account. The corrections are listed below, highlighted by a boldface font.
2 citations
Posted Content•
TL;DR: In this article, the authors show that the response of muon detectors to atmospheric and geomagnetic effects is consistent with those from other locations by comparing intensity variations during a space weather event.
Abstract: Muon detectors and neutron monitors were recently installed at Syowa Station, in the Antarctic, to observe different types of secondary particles resulting from cosmic ray interactions simultaneously from the same location. Continuing observations will give new insight into the response of muon detectors to atmospheric and geomagnetic effects. Operation began in February, 2018 and the system has been stable with a duty-cycle exceeding 94%. Muon data shows a clear seasonal variation, which is expected from the atmospheric temperature effect. We verified successful operation by showing that the muon and neutron data are consistent with those from other locations by comparing intensity variations during a space weather event. We have established a web page to make real time data available with interactive graphics (this http URL).