Pub Date : 2022-09-01DOI: 10.5140/jass.2022.39.3.109
Hosub Song, Jaejin Lee, Y. Yi
The small-scale magnetospheric and ionospheric plasma experiment (SNIPE) is a mission initiated by the Korea Astronomy and Space Science Institute (KASI) in 2017 and comprises four 6U-sized nano-satellites (Korea Astronomy and Space Science Institute Satellite-1, KASISat-1) flying in formations. The main goal of the SNIPE mission is to investigate the space environment in low Earth orbit at 500-km. Because Iridium & GPS Board (IGB) is installed on the KASISat-1, a communication simulation is required to analyze the contact number and the duration. In this study, communication simulations between the Iridium satellite network and KASISat-1 are performed using STK Pro (System Tool Kit Pro Ver 11.2) from the AGI (Analytical Graphics, Inc.). The contact number and durations were analyzed by each orbit and date. The analysis shows that the average access number per day is 38.714 times, with an average of 2.533 times per orbit for a week. Furthermore, on average, the Iridium satellite communication is linked for 70.597 min daily. Moreover, 4.625 min is the average duration of an individual orbit.
小规模磁层和电离层等离子体实验(SNIPE)是韩国天文空间科学研究院(KASI)于2017年启动的一项任务，由4颗6u大小的纳米卫星(韩国天文空间科学研究院卫星1号，KASISat-1)组成。SNIPE任务的主要目标是在近地轨道500公里处调查空间环境。由于在KASISat-1上安装了铱星和GPS板(IGB)，因此需要进行通信模拟来分析联系号码和持续时间。在本研究中，铱星网络和KASISat-1之间的通信模拟使用来自AGI (Analytical Graphics, Inc.)的STK Pro (System Tool Kit Pro Ver 11.2)进行。根据每个轨道和日期分析了接触次数和持续时间。分析显示，平均每天访问次数为38.714次，平均每周每轨道访问次数为2.533次。此外，铱星通信平均每天连接70.597分钟。此外，4.625分钟是单个轨道的平均持续时间。
{"title":"Feasibility Study of Communication Access via Iridium Constellation for Small-Scale\u0000 Magnetospheric Ionospheric Plasma Experiment Mission","authors":"Hosub Song, Jaejin Lee, Y. Yi","doi":"10.5140/jass.2022.39.3.109","DOIUrl":"https://doi.org/10.5140/jass.2022.39.3.109","url":null,"abstract":"The small-scale magnetospheric and ionospheric plasma experiment (SNIPE) is a\u0000 mission initiated by the Korea Astronomy and Space Science Institute (KASI) in 2017 and\u0000 comprises four 6U-sized nano-satellites (Korea Astronomy and Space Science Institute\u0000 Satellite-1, KASISat-1) flying in formations. The main goal of the SNIPE mission is to\u0000 investigate the space environment in low Earth orbit at 500-km. Because Iridium &\u0000 GPS Board (IGB) is installed on the KASISat-1, a communication simulation is required to\u0000 analyze the contact number and the duration. In this study, communication simulations\u0000 between the Iridium satellite network and KASISat-1 are performed using STK Pro (System\u0000 Tool Kit Pro Ver 11.2) from the AGI (Analytical Graphics, Inc.). The contact number and\u0000 durations were analyzed by each orbit and date. The analysis shows that the average\u0000 access number per day is 38.714 times, with an average of 2.533 times per orbit for a\u0000 week. Furthermore, on average, the Iridium satellite communication is linked for 70.597\u0000 min daily. Moreover, 4.625 min is the average duration of an individual orbit.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82843218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-01DOI: 10.5140/jass.2022.39.3.79
Qian Wu, D. Lin, Wenbin Wang, W. Ward
Thermospheric wind observations from high to mid latitudes are compared with the newly developed Multiscale Atmosphere Geospace Environment (MAGE) model for the Nov 3–4 geomagnetic storm. The observation and simulation comparison shows a very good agreement and is better at high latitudes in general. We were able to identify a thermospheric poleward wind reduction possibly linked to a northward turning of the Interplanetary Magnetic Field (IMF) at ~22 UT on Nov 3 and an enhancement of the poleward wind to a southward turning near 10 UT on Nov 4 at high latitudes. An IMF southward turning may have led to an enhancement of equatorward winds at Boulder, Colorado near midnight. Simultaneous occurrence of aurora may be associated with an IMF By turning negative. The MAGE model wind simulations are consistent with observations in these cases. The results show the model can be a very useful tool to further study the magnetosphere and ionosphere coupling on short time scales.
{"title":"Thermospheric Wind Observation and Simulation during the Nov 4, 2021 Geomagnetic\u0000 Storm Event","authors":"Qian Wu, D. Lin, Wenbin Wang, W. Ward","doi":"10.5140/jass.2022.39.3.79","DOIUrl":"https://doi.org/10.5140/jass.2022.39.3.79","url":null,"abstract":"Thermospheric wind observations from high to mid latitudes are compared with the\u0000 newly developed Multiscale Atmosphere Geospace Environment (MAGE) model for the Nov 3–4\u0000 geomagnetic storm. The observation and simulation comparison shows a very good agreement\u0000 and is better at high latitudes in general. We were able to identify a thermospheric\u0000 poleward wind reduction possibly linked to a northward turning of the Interplanetary\u0000 Magnetic Field (IMF) at ~22 UT on Nov 3 and an enhancement of the poleward wind to a\u0000 southward turning near 10 UT on Nov 4 at high latitudes. An IMF southward turning may\u0000 have led to an enhancement of equatorward winds at Boulder, Colorado near midnight.\u0000 Simultaneous occurrence of aurora may be associated with an IMF By turning negative. The\u0000 MAGE model wind simulations are consistent with observations in these cases. The results\u0000 show the model can be a very useful tool to further study the magnetosphere and\u0000 ionosphere coupling on short time scales.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73488396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-01DOI: 10.5140/jass.2022.39.3.87
Jaeheung Park, S. Mende, R. Eastes, H. Frey
The Far-UltraViolet (FUV) imager onboard the Ionospheric Connection Explorer (ICON) spacecraft provides two-dimensional limb images of oxygen airglow in the nightside low-latitude ionosphere that are used to determine the oxygen ion density. As yet, no FUV limb imager has been used for climatological analyses of Equatorial Plasma Bubbles (EPBs). To examine the potential of ICON/FUV for this purpose, we statistically investigate small-scale (~180 km) fluctuations of oxygen ion density in its limb images. The seasonal-longitudinal variations of the fluctuation level reasonably conform to the EPB statistics in existing literature. To further validate the ICON/FUV data quality, we also inspect climatology of the ambient (unfiltered) nightside oxygen ion density. The ambient density exhibits (1) the well-known zonal wavenumber-4 signatures in the Equatorial Ionization Anomaly (EIA) and (2) off-equatorial enhancement above the Caribbean, both of which agree with previous studies. Merits of ICON/FUV observations over other conventional data sets are discussed in this paper. Furthermore, we suggest possible directions of future work, e.g., synergy between ICON/FUV and the Global-scale Observations of the Limb and Disk (GOLD) mission.
{"title":"Climatology of Equatorial Plasma Bubbles in Ionospheric Connection\u0000 Explorer/Far-UltraViolet (ICON/FUV) Limb Images","authors":"Jaeheung Park, S. Mende, R. Eastes, H. Frey","doi":"10.5140/jass.2022.39.3.87","DOIUrl":"https://doi.org/10.5140/jass.2022.39.3.87","url":null,"abstract":"The Far-UltraViolet (FUV) imager onboard the Ionospheric Connection Explorer\u0000 (ICON) spacecraft provides two-dimensional limb images of oxygen airglow in the\u0000 nightside low-latitude ionosphere that are used to determine the oxygen ion density. As\u0000 yet, no FUV limb imager has been used for climatological analyses of Equatorial Plasma\u0000 Bubbles (EPBs). To examine the potential of ICON/FUV for this purpose, we statistically\u0000 investigate small-scale (~180 km) fluctuations of oxygen ion density in its limb images.\u0000 The seasonal-longitudinal variations of the fluctuation level reasonably conform to the\u0000 EPB statistics in existing literature. To further validate the ICON/FUV data quality, we\u0000 also inspect climatology of the ambient (unfiltered) nightside oxygen ion density. The\u0000 ambient density exhibits (1) the well-known zonal wavenumber-4 signatures in the\u0000 Equatorial Ionization Anomaly (EIA) and (2) off-equatorial enhancement above the\u0000 Caribbean, both of which agree with previous studies. Merits of ICON/FUV observations\u0000 over other conventional data sets are discussed in this paper. Furthermore, we suggest\u0000 possible directions of future work, e.g., synergy between ICON/FUV and the Global-scale\u0000 Observations of the Limb and Disk (GOLD) mission.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90176087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-01DOI: 10.5140/jass.2022.39.3.117
K. Ryu, Seunguk Lee, C. Woo, Junchan Lee, E. Jang, Jaemin Hwang, Jin-Kyu Kim, Wonho Cha, Dong-guk Kim, BonJu Koo, S. Park, Dooyoung Choi, C.‐R. Choi
The Ionospheric Anomaly Monitoring by Magnetometer And Plasma-probe (IAMMAP) is one of the scientific instruments for the Compact Advanced Satellite 500-3 (CAS 500-3) which is planned to be launched by Korean Space Launch Vehicle in 2024. The main scientific objective of IAMMAP is to understand the complicated correlation between the equatorial electro-jet (EEJ) and the equatorial ionization anomaly (EIA) which play important roles in the dynamics of the ionospheric plasma in the dayside equator region. IAMMAP consists of an impedance probe (IP) for precise plasma measurement and magnetometers for EEJ current estimation. The designated sun-synchronous orbit along the quasi-meridional plane makes the instrument suitable for studying the EIA and EEJ. The newly-devised IP is expected to obtain the electron density of the ionosphere with unprecedented precision by measuring the upper-hybrid frequency (fUHR) of the ionospheric plasma, which is not affected by the satellite geometry, the spacecraft potential, or contamination unlike conventional Langmuir probes. A set of temperaturetolerant precision fluxgate magnetometers, called Adaptive In-phase MAGnetometer, is employed also for studying the complicated current system in the ionosphere and magnetosphere, which is particularly related with the EEJ caused by the potential difference along the zonal direction.
{"title":"Science Objectives and Design of Ionospheric Monitoring Instrument Ionospheric\u0000 Anomaly Monitoring by Magnetometer And Plasmaprobe (IAMMAP) for the CAS500-3\u0000 Satellite","authors":"K. Ryu, Seunguk Lee, C. Woo, Junchan Lee, E. Jang, Jaemin Hwang, Jin-Kyu Kim, Wonho Cha, Dong-guk Kim, BonJu Koo, S. Park, Dooyoung Choi, C.‐R. Choi","doi":"10.5140/jass.2022.39.3.117","DOIUrl":"https://doi.org/10.5140/jass.2022.39.3.117","url":null,"abstract":"The Ionospheric Anomaly Monitoring by Magnetometer And Plasma-probe (IAMMAP) is\u0000 one of the scientific instruments for the Compact Advanced Satellite 500-3 (CAS 500-3)\u0000 which is planned to be launched by Korean Space Launch Vehicle in 2024. The main\u0000 scientific objective of IAMMAP is to understand the complicated correlation between the\u0000 equatorial electro-jet (EEJ) and the equatorial ionization anomaly (EIA) which play\u0000 important roles in the dynamics of the ionospheric plasma in the dayside equator region.\u0000 IAMMAP consists of an impedance probe (IP) for precise plasma measurement and\u0000 magnetometers for EEJ current estimation. The designated sun-synchronous orbit along the\u0000 quasi-meridional plane makes the instrument suitable for studying the EIA and EEJ. The\u0000 newly-devised IP is expected to obtain the electron density of the ionosphere with\u0000 unprecedented precision by measuring the upper-hybrid frequency (fUHR) of the\u0000 ionospheric plasma, which is not affected by the satellite geometry, the spacecraft\u0000 potential, or contamination unlike conventional Langmuir probes. A set of\u0000 temperaturetolerant precision fluxgate magnetometers, called Adaptive In-phase\u0000 MAGnetometer, is employed also for studying the complicated current system in the\u0000 ionosphere and magnetosphere, which is particularly related with the EEJ caused by the\u0000 potential difference along the zonal direction.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85689248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-01DOI: 10.5140/jass.2022.39.3.99
Y. Portnov
There are two models that explain the rotation curves of galaxies: dark matter, which gives the missing contribution to the gravitational potential of the standard theory of gravity, and modified theories of gravity, according to which the gravitational potential is created by ordinary visible mass. Both models have some disadvantages. The article offers a new look at the problem of galactic rotation curves. The author suggests that the moment of inertia creates an additional gravitational potential along with the mass. The numerical simulation carried out on the example of fourteen galaxies confirms the validity of such an assumption. This approach makes it possible to explain the constancy of gas velocities outside the galactic disk without involving the hypothesis of the existence of dark matter. At the same time, the proposed approach lacks the disadvantages of modified theories of gravity, where the gravitational potential is created only by the mass of visible matter.
{"title":"On the Influence of the Moment of Inertia of Gas on the Galactic Rotation\u0000 Curves","authors":"Y. Portnov","doi":"10.5140/jass.2022.39.3.99","DOIUrl":"https://doi.org/10.5140/jass.2022.39.3.99","url":null,"abstract":"There are two models that explain the rotation curves of galaxies: dark matter,\u0000 which gives the missing contribution to the gravitational potential of the standard\u0000 theory of gravity, and modified theories of gravity, according to which the\u0000 gravitational potential is created by ordinary visible mass. Both models have some\u0000 disadvantages. The article offers a new look at the problem of galactic rotation curves.\u0000 The author suggests that the moment of inertia creates an additional gravitational\u0000 potential along with the mass. The numerical simulation carried out on the example of\u0000 fourteen galaxies confirms the validity of such an assumption. This approach makes it\u0000 possible to explain the constancy of gas velocities outside the galactic disk without\u0000 involving the hypothesis of the existence of dark matter. At the same time, the proposed\u0000 approach lacks the disadvantages of modified theories of gravity, where the\u0000 gravitational potential is created only by the mass of visible matter.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72431665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-01DOI: 10.5140/jass.2022.39.2.67
K. N. Shukla, J. Kumari, R. S. Pandey
The elements that impact the dynamics and collaborations of waves and particles in the magnetosphere of planets have been considered here. Saturn’s internal magnetosphere is determined by substantiated instabilities and discovered to be an exceptional zone of wave activity. Interchanged instability is found to be one of the responsible events in view of temperature anisotropy and energization processes of magnetospheric species. The generated active ions alongside electrons that constitute the populations of highly magnetized planets like Saturn’s ring electron current are taken into consideration in the current framework. The previous and similar method of characteristics and the perturbed distribution function have been used to derive dispersion relation. In incorporating this investigation, the characteristics of electromagnetic ion cyclotron wave (EMIC) waves are determined by the composition of ions in plasmas through which the waves propagate. The effect of ring distribution illustrates non-monotonous description on growth rate (GR) depending upon plasma parameters picked out. Observations made by Cassini found appropriate for modern study, have been applied to the Kronian magnetosphere. Using Maxwellian ring distribution function of ions and detailed mathematical formulation, an expression for dispersion relation as well as GR and real frequency (RF) are evaluated. Analysis of plasma parameters shows that, proliferating EMIC waves are not developed much when propagation is parallelly aligned with magnetosphere as compared to waves propagating in oblique direction. GR for the oblique case, is influenced by temperature anisotropy as well as by alternating current (AC) frequency, whereas it is much affected only by AC frequency for parallel propagating waves.
{"title":"Interaction of Ion Cyclotron Electromagnetic Wave with Energetic Particles in the\u0000 Existence of Alternating Electric Field Using Ring Distribution","authors":"K. N. Shukla, J. Kumari, R. S. Pandey","doi":"10.5140/jass.2022.39.2.67","DOIUrl":"https://doi.org/10.5140/jass.2022.39.2.67","url":null,"abstract":"The elements that impact the dynamics and collaborations of waves and particles\u0000 in the magnetosphere of planets have been considered here. Saturn’s internal\u0000 magnetosphere is determined by substantiated instabilities and discovered to be an\u0000 exceptional zone of wave activity. Interchanged instability is found to be one of the\u0000 responsible events in view of temperature anisotropy and energization processes of\u0000 magnetospheric species. The generated active ions alongside electrons that constitute\u0000 the populations of highly magnetized planets like Saturn’s ring electron current are\u0000 taken into consideration in the current framework. The previous and similar method of\u0000 characteristics and the perturbed distribution function have been used to derive\u0000 dispersion relation. In incorporating this investigation, the characteristics of\u0000 electromagnetic ion cyclotron wave (EMIC) waves are determined by the composition of\u0000 ions in plasmas through which the waves propagate. The effect of ring distribution\u0000 illustrates non-monotonous description on growth rate (GR) depending upon plasma\u0000 parameters picked out. Observations made by Cassini found appropriate for modern study,\u0000 have been applied to the Kronian magnetosphere. Using Maxwellian ring distribution\u0000 function of ions and detailed mathematical formulation, an expression for dispersion\u0000 relation as well as GR and real frequency (RF) are evaluated. Analysis of plasma\u0000 parameters shows that, proliferating EMIC waves are not developed much when propagation\u0000 is parallelly aligned with magnetosphere as compared to waves propagating in oblique\u0000 direction. GR for the oblique case, is influenced by temperature anisotropy as well as\u0000 by alternating current (AC) frequency, whereas it is much affected only by AC frequency\u0000 for parallel propagating waves.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88663510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-01DOI: 10.5140/jass.2022.39.2.59
Y. Portnov
In this paper we propose a new perspective for explaining galaxy rotation curves. We conjecture that there is a gravitational moment of inertia which, together with gravitational mass, contributes to the gravitational potential. We substantiate a formula for the potential created by the moment of inertia. We validate our model by computing orbital rotation velocities for several galaxies and showing that computed rotation velocities correspond to the observed ones. Our proposed approach is capable of accounting for constant gas velocities outside of a galactic disc without relying on the dark matter hypothesis. Furthermore, it addresses several problems faced by the application of the dark matter hypothesis, e.g., the absence of inward collapse of dark matter into a galaxy, the spherical distribution of dark matter around galaxies, and absence of traces of the effect of dark matter in two ultra-diffuse galaxies, NGC 1052-DF2, and NGC 1052-DF4.
{"title":"Moment of Inertia of Gas as a Source of Added Gravitational Field in\u0000 Galaxies","authors":"Y. Portnov","doi":"10.5140/jass.2022.39.2.59","DOIUrl":"https://doi.org/10.5140/jass.2022.39.2.59","url":null,"abstract":"In this paper we propose a new perspective for explaining galaxy rotation curves.\u0000 We conjecture that there is a gravitational moment of inertia which, together with\u0000 gravitational mass, contributes to the gravitational potential. We substantiate a\u0000 formula for the potential created by the moment of inertia. We validate our model by\u0000 computing orbital rotation velocities for several galaxies and showing that computed\u0000 rotation velocities correspond to the observed ones. Our proposed approach is capable of\u0000 accounting for constant gas velocities outside of a galactic disc without relying on the\u0000 dark matter hypothesis. Furthermore, it addresses several problems faced by the\u0000 application of the dark matter hypothesis, e.g., the absence of inward collapse of dark\u0000 matter into a galaxy, the spherical distribution of dark matter around galaxies, and\u0000 absence of traces of the effect of dark matter in two ultra-diffuse galaxies, NGC\u0000 1052-DF2, and NGC 1052-DF4.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74037601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-01DOI: 10.5140/jass.2022.39.2.51
Hee-Bok Ahn, Jung-Lae Hwang, Jaeyoung Kwak, Kyuwang Kim
Cosmic radiation exposure of the flight crews in Korea has been managed by Radiation Safety Management around Living Life Act under Nuclear Safety and Security Commission. However, the domestic flight crews are excluded from the Act because of relatively low route dose exposure compared to that of international flight crews. But we found that the accumulated total annual dose of domestic flight crews is far from negligible because of relatively long total flight time and too many flights. In this study, to suggest the necessity of management of domestic flight crews’ radiation exposure, we statistically analyzed domestic flight crew’s accumulative annual dose by using cosmic radiation estimation models of the Civil Aviation Research Institute (CARI)-6M, Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS), and Korean Radiation Exposure Assessment Model (KREAM) and compared with in-situ measurements of Liulin-6K LET spectrometer. As a result, the average exposure dose of domestic flight crews was found to be 0.5–0.8 mSv. We also expect that our result might provide the basis to include the domestic flight crews as radiation workers, not just international flight attendants.
{"title":"Analysis of Cosmic Radiation Exposure for Domestic Flight Crews in Korea","authors":"Hee-Bok Ahn, Jung-Lae Hwang, Jaeyoung Kwak, Kyuwang Kim","doi":"10.5140/jass.2022.39.2.51","DOIUrl":"https://doi.org/10.5140/jass.2022.39.2.51","url":null,"abstract":"Cosmic radiation exposure of the flight crews in Korea has been managed by\u0000 Radiation Safety Management around Living Life Act under Nuclear Safety and Security\u0000 Commission. However, the domestic flight crews are excluded from the Act because of\u0000 relatively low route dose exposure compared to that of international flight crews. But\u0000 we found that the accumulated total annual dose of domestic flight crews is far from\u0000 negligible because of relatively long total flight time and too many flights. In this\u0000 study, to suggest the necessity of management of domestic flight crews’ radiation\u0000 exposure, we statistically analyzed domestic flight crew’s accumulative annual dose by\u0000 using cosmic radiation estimation models of the Civil Aviation Research Institute\u0000 (CARI)-6M, Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS), and\u0000 Korean Radiation Exposure Assessment Model (KREAM) and compared with in-situ\u0000 measurements of Liulin-6K LET spectrometer. As a result, the average exposure dose of\u0000 domestic flight crews was found to be 0.5–0.8 mSv. We also expect that our result might\u0000 provide the basis to include the domestic flight crews as radiation workers, not just\u0000 international flight attendants.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84463883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-01DOI: 10.5140/jass.2022.39.2.43
E. U. Iyida, Innocent Okwudili Eya, C. I. Eze
The unified scheme of Seyfert galaxies hypothesizes that the observed differences between the two categories of Seyfert galaxies, type 1 (Sy1) and type 2 (Sy2) are merely due to the difference in the orientation of the toroidal shape of the obscuring material in the active galactic nuclei. We used in this paper, a sample consisting of 120 Seyfert galaxies at 1.40 × 109 Hz in radio, 2.52 × 1017 Hz in X-ray and 2.52 × 1023 Hz in γ-ray luminosities observed by the Fermi Large Area Telescope (Fermi- LAT) in order to test the unified scheme of radio-quiet Seyfert galaxies. Our main results are as follows: (i) We found that the distributions of multiwave luminosities (Lradio, LX-ray, and Lγ-ray) of Sy1 and Sy2 are completely overlapped with up to a factor of 4. The principal component analysis result reveals that Sy1 and Sy2 also occupy the same parameter spaces, which agrees with the notion that Sy1 and Sy2 are the same class objects. A Kolmogorov-Smirnov test performed on the sub-samples indicates that the null hypothesis (both are from the same population) cannot be rejected with chance probability p ~ 0 and separation distance K = 0.013. This result supports the fact that there is no statistical difference between the properties of Sy1 and Sy2 (ii) We found that the coefficient of the best-fit linear regression equation between the common properties of Sy1 and Sy2 is significant (r > 0.50) which plausibly implies that Sy1 and Sy2 are the same type of objects observed at different viewing angle.
{"title":"Testing the Consistency of Unified Scheme of Seyfert Galaxies","authors":"E. U. Iyida, Innocent Okwudili Eya, C. I. Eze","doi":"10.5140/jass.2022.39.2.43","DOIUrl":"https://doi.org/10.5140/jass.2022.39.2.43","url":null,"abstract":"The unified scheme of Seyfert galaxies hypothesizes that the observed differences\u0000 between the two categories of Seyfert galaxies, type 1 (Sy1) and type 2 (Sy2) are merely\u0000 due to the difference in the orientation of the toroidal shape of the obscuring material\u0000 in the active galactic nuclei. We used in this paper, a sample consisting of 120 Seyfert\u0000 galaxies at 1.40 × 109 Hz in radio, 2.52 × 1017 Hz in X-ray and 2.52 × 1023 Hz in γ-ray\u0000 luminosities observed by the Fermi Large Area Telescope (Fermi- LAT) in order to test\u0000 the unified scheme of radio-quiet Seyfert galaxies. Our main results are as follows: (i)\u0000 We found that the distributions of multiwave luminosities (Lradio, LX-ray, and Lγ-ray)\u0000 of Sy1 and Sy2 are completely overlapped with up to a factor of 4. The principal\u0000 component analysis result reveals that Sy1 and Sy2 also occupy the same parameter\u0000 spaces, which agrees with the notion that Sy1 and Sy2 are the same class objects. A\u0000 Kolmogorov-Smirnov test performed on the sub-samples indicates that the null hypothesis\u0000 (both are from the same population) cannot be rejected with chance probability p ~ 0 and\u0000 separation distance K = 0.013. This result supports the fact that there is no\u0000 statistical difference between the properties of Sy1 and Sy2 (ii) We found that the\u0000 coefficient of the best-fit linear regression equation between the common properties of\u0000 Sy1 and Sy2 is significant (r > 0.50) which plausibly implies that Sy1 and Sy2 are\u0000 the same type of objects observed at different viewing angle.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88148807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-01DOI: 10.5140/jass.2022.39.2.23
H. Kil
Electron density irregularities in the equatorial ionosphere at night are understood in terms of plasma bubbles, which are produced by the transport of low-density plasma from the bottomside of the F region to the topside. Equatorial plasma bubbles (EPBs) have been detected by various techniques on the ground and from space. One of the distinguishing characteristics of EPBs identified from long-term observations is the systematic seasonal and longitudinal variation of the EPB activity. Several hypotheses have been developed to explain the systematic EPB behavior, and now we have good knowledge about the key factors that determine the behavior. However, gaps in our understanding of the EPB climatology still remain primarily because we do not yet have the capability to observe seed perturbations and their growth simultaneously and globally. This paper reviews the occurrence climatology of EPBs identified from observations and the current understanding of its driving mechanisms.
{"title":"The Occurrence Climatology of Equatorial Plasma Bubbles: A Review","authors":"H. Kil","doi":"10.5140/jass.2022.39.2.23","DOIUrl":"https://doi.org/10.5140/jass.2022.39.2.23","url":null,"abstract":"Electron density irregularities in the equatorial ionosphere at night are\u0000 understood in terms of plasma bubbles, which are produced by the transport of\u0000 low-density plasma from the bottomside of the F region to the topside. Equatorial plasma\u0000 bubbles (EPBs) have been detected by various techniques on the ground and from space.\u0000 One of the distinguishing characteristics of EPBs identified from long-term observations\u0000 is the systematic seasonal and longitudinal variation of the EPB activity. Several\u0000 hypotheses have been developed to explain the systematic EPB behavior, and now we have\u0000 good knowledge about the key factors that determine the behavior. However, gaps in our\u0000 understanding of the EPB climatology still remain primarily because we do not yet have\u0000 the capability to observe seed perturbations and their growth simultaneously and\u0000 globally. This paper reviews the occurrence climatology of EPBs identified from\u0000 observations and the current understanding of its driving mechanisms.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87260581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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