https://repository.kopri.re.kr/handle/201206/13381 Sun, 05 Apr 2026 05:03:18 GMT 2026-04-05T05:03:18Z https://repository.kopri.re.kr/handle/201206/14552 Title: A study of propagation of ULF waves using Antarctic magnetometer network and satellite measurements Authors: Kwon, Hyuck-Jin Fri, 28 Jul 2023 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/14552 2023-07-28T00:00:00Z https://repository.kopri.re.kr/handle/201206/14096 Title: Disappearance of the Polar Cap Ionosphere During Geomagnetic Storm on 11 May 2019 Authors: Kwon, Hyuck-Jin; 김관혁; Jee, Geonhwa; 선종호; Lee, Changsup; Ham, Young-Bae; 홍준석; 김은솔; Terry Bullett; Uli Auster; Wener Magnes; Stephan Kraft Abstract: Multi-instrument data from Jang Bogo Station (JBS) in Antarctica were utilized to study ionospheric responses to the 11 May 2019 moderate geomagnetic storm. These include Vertical Incident Pulsed Ionospheric Radar (VIPIR)/Dynasonde, Fabry-Perot Interferometer (FPI), GPS vertical total electron content (vTEC), and magnetometer.The VIPIR/Dynasonde observed long-lasting (> 11 h) severe depletion of the electron density in the F-region ionosphere over JBS. During the depletion interval, GPS TEC also correspondingly decreased, FPI neutral temperature was significantly enhanced, and the polar magnetic field variations showed positive and negative excursions in the Y(east)and Z(vertical)components, respectively. GK-2A satellite, located ~2.5 hr west of JBS, observed negative magnetic field perturbations in the azimuthal BDcomponent at geosynchronous orbit during the depletion of ionospheric plasma. Such a BDperturbation at geosynchronous orbit is due to the field-aligned currents flowing out of the ionosphere. From these observations we suggest that transpolar ionosphericcurrents connected to the field-aligned currents flowing on a substorm wedge-shaped circuit act as a source of polar atmospheric heating during the moderate geomagnetic storm interval and that elevated heavy molecular gases (O2and N2) by atmospheric heating contribute to the electron density depletion viaincreased recombination rate. Sat, 01 Jan 2022 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/14096 2022-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/14122 Title: Review of Environmental Monitoring by Means of Radio Waves in the Polar Regions: From Atmosphere to Geospace Authors: Lucilla Alfonsi; Nicolar Bergeot; Pierre J. Cilliers; Giorgiana De Franceschi; Lisa Baddeley; Emilia Correia; Domenico Di Mauro; Carl-Fredrik Enell; Mark Engebretson; Reza Ghoddousi-Fard; Ingemar Haggstrom; Ham, Young-Bae; Georg Heygster; Jee, Geonhwa; Antti Kero; Michael Kosch; Kwon, Hyuck-Jin; Lee, Changsup; Stefan Lotz; Liliana Macotela; Maria Federica Marcucci; Wojciech J. Miloch; Y. Jade Morton; Takahiro Naoi; Monia negusini; Noora Partamies; Boyan H. Petkov; Eric Pottiaux; Paul Prikryl; P. R. Shreedevi; Rikard Slapak; Luca Spogli; Judy Stephenson; Arantxa M. Triana-Gomez; Oleg A. Troshichev; Roeland Van Malderen; James M. Weygand; Shasha Zou Abstract: The Antarctic and Arctic regions are Earth's open windows to the outer space. They provide unique opportunities for investigating the troposphere-thermosphere-ionosphere-plasmasphere system at high latitudes, which is not as well understood as the mid and low-latitude regions mainly due to the paucity of experimental observations. In addition, the different neutral and ionized atmospheric layers at high latitudes are much more variable compared to other latitudes, and their variability is due to mechanisms not yet fully understood. Fortunately, since the 2000’s the observing infrastructure in Antarctica and the Arctic has been growing, thus providing scientists with new opportunities to advance the knowledge on the polar atmosphere and geospace. This review shows that it is of paramount importance to perform integrated, multi-disciplinary research, making use of long-term multi-instrument observations combined with ad hoc measurement campaigns to improve our capability of investigating atmospheric dynamics in polar regions from the troposphere up to the plasmasphere, as well as the coupling between atmospheric layers. Starting from the state of the art of understanding the polar atmosphere, our survey outlines the roadmap for enhancing scientific investigation of its physical mechanisms and dynamics through the full exploitation of the available infrastructures for radio-based environmental monitoring. Sat, 01 Jan 2022 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/14122 2022-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/14098 Title: Spacecraft Potential Changes Associated With EMIC Waves in the Inner Magnetosphere Authors: 김관혁; 이준현; 권종우; 이은상; 김희은; 진호; Kwon, Hyuck-Jin; 백슬민; John Wygant; Forrest S. Mozer Abstract: Although electromagnetic ion cyclotron (EMIC) waves are commonly observed in the magnetosphere and are believed to energize background cold ions, it is not clear whether EMIC waves play a significant role in determining spacecraft potential change. In this paper, we present two strong He-band EMIC wave events observed by the Van Allen Probe-B spacecraft inside the plasmasphere. One event occurred on 11 March 2016 when the spacecraft was on the dayside, and the other occurred on 9 October 2016 when the spacecraft was in the postmidnight sector. When a strong He-band EMIC wave activity was detected, low-energy ion flux enhancements occurred nearly simultaneously with the EMIC wave power enhancements. Both events presented in this study are clearly unique in that He-band wave power and enhanced proton flux are extremely high. During the wave activity interval, we found that the spacecraft charged more positively without a significant change in the ambient electron density. We discuss whether low-energy ions energized by EMIC waves can contribute to the spacecraft potential change. Sat, 01 Jan 2022 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/14098 2022-01-01T00:00:00Z