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Found 114 entries in the Bibliography.
Showing entries from 1 through 50
| 2022 |
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In the White Paper, submitted in response to the European Space Agency (ESA) Voyage 2050 Call, we present the importance of advancing our knowledge of plasma-neutral gas interactions, and of deepening our understanding of the partially ionized environments that are ubiquitous in the upper atmospheres of planets and moons, and elsewhere in space. In future space missions, the above task requires addressing the following fundamental questions: (A) How and by how much do plasma-neutral gas interactions influence the re-distribution of externally provided energy to the composing species? (B) How and by how much do plasma-neutral gas interactions contribute toward the growth of heavy complex molecules and biomolecules? Answering these questions is an absolute prerequisite for addressing the long-standing questions of atmospheric escape, the origin of biomolecules, and their role in the evolution of planets, moons, or comets, under the influence of energy sources in the form of electromagnetic and corpuscular radiation, because low-energy ion-neutral cross-sections in space cannot be reproduced quantitatively in laboratories for conditions of satisfying, particularly, (1) low-temperatures, (2) tenuous or strong gradients or layered media, and (3) in low-gravity plasma. Measurements with a minimum core instrument package (\textless 15 kg) can be used to perform such investigations in many different conditions and should be included in all deep-space missions. These investigations, if specific ranges of background parameters are considered, can also be pursued for Earth, Mars, and Venus. Yamauchi, Masatoshi; De Keyser, Johan; Parks, George; Oyama, Shin-ichiro; Wurz, Peter; Abe, Takumi; Beth, Arnaud; Daglis, Ioannis; Dandouras, Iannis; Dunlop, Malcolm; Henri, Pierre; Ivchenko, Nickolay; Kallio, Esa; Kucharek, Harald; Liu, Yong; Mann, Ingrid; Marghitu, Octav; Nicolaou, Georgios; Rong, Zhaojin; Sakanoi, Takeshi; Saur, Joachim; Shimoyama, Manabu; Taguchi, Satoshi; Tian, Feng; Tsuda, Takuo; Tsurutani, Bruce; Turner, Drew; Ulich, Thomas; Yau, Andrew; Yoshikawa, Ichiro; Published by: Experimental Astronomy Published on: mar YEAR: 2022 DOI: 10.1007/s10686-022-09846-9 Collision cross-section; Future missions; Low-energy; Neutral gas; Plasma; Voyage 2050 |
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In the White Paper, submitted in response to the European Space Agency (ESA) Voyage 2050 Call, we present the importance of advancing our knowledge of plasma-neutral gas interactions, and of deepening our understanding of the partially ionized environments that are ubiquitous in the upper atmospheres of planets and moons, and elsewhere in space. In future space missions, the above task requires addressing the following fundamental questions: (A) How and by how much do plasma-neutral gas interactions influence the re-distribution of externally provided energy to the composing species? (B) How and by how much do plasma-neutral gas interactions contribute toward the growth of heavy complex molecules and biomolecules? Answering these questions is an absolute prerequisite for addressing the long-standing questions of atmospheric escape, the origin of biomolecules, and their role in the evolution of planets, moons, or comets, under the influence of energy sources in the form of electromagnetic and corpuscular radiation, because low-energy ion-neutral cross-sections in space cannot be reproduced quantitatively in laboratories for conditions of satisfying, particularly, (1) low-temperatures, (2) tenuous or strong gradients or layered media, and (3) in low-gravity plasma. Measurements with a minimum core instrument package (\textless 15 kg) can be used to perform such investigations in many different conditions and should be included in all deep-space missions. These investigations, if specific ranges of background parameters are considered, can also be pursued for Earth, Mars, and Venus. Yamauchi, Masatoshi; De Keyser, Johan; Parks, George; Oyama, Shin-ichiro; Wurz, Peter; Abe, Takumi; Beth, Arnaud; Daglis, Ioannis; Dandouras, Iannis; Dunlop, Malcolm; Henri, Pierre; Ivchenko, Nickolay; Kallio, Esa; Kucharek, Harald; Liu, Yong; Mann, Ingrid; Marghitu, Octav; Nicolaou, Georgios; Rong, Zhaojin; Sakanoi, Takeshi; Saur, Joachim; Shimoyama, Manabu; Taguchi, Satoshi; Tian, Feng; Tsuda, Takuo; Tsurutani, Bruce; Turner, Drew; Ulich, Thomas; Yau, Andrew; Yoshikawa, Ichiro; Published by: Experimental Astronomy Published on: mar YEAR: 2022 DOI: 10.1007/s10686-022-09846-9 Collision cross-section; Future missions; Low-energy; Neutral gas; Plasma; Voyage 2050 |
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Chapter 4 - Energetic particle dynamics, precipitation, and conductivity This chapter reviews cross-scale coupling and energy transfer in the magnetosphere-ionosphere-thermosphere system via convection, precipitation, and conductance. It begins with an introduction into Earth’s plasma sheet characteristics including particles, plasma moments, and magnetic fields, and their dependence on solar wind and interplanetary magnetic field parameters. Section 4.2 transitions to observations of the magnetosphere convection, precipitation, and coupling with the ionosphere on multiple scales, with Section 4.3 focusing on related global modeling efforts for particle precipitation. This chapter describes basic concepts and principles of major pitch angle scattering processes—wave-particle interactions and field-line curvature scattering—as well as the resulting precipitation and conductance. Section 4.4 continues the discussion started in 4.2 Observations of multiscale convection, precipitation, and conductivity, 4.3 Simulating particle precipitation of magnetospheric origin in global models regarding the resulting ionosphere conductance, delving more deeply into empirical and data assimilative techniques. This chapter describes techniques used over the years to observe and model precipitation and conductance on multiple scales. Gabrielse, Christine; Kaeppler, Stephen; Lu, Gang; Wang, Chih-Ping; Yu, Yiqun; Nishimura, Yukitoshi; Verkhoglyadova, Olga; Deng, Yue; Zhang, Shun-Rong; Published by: Published on: jan YEAR: 2022 DOI: 10.1016/B978-0-12-821366-7.00002-0 Conductance; Conductivity; Convection; particle precipitation |
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Optomechanical design of a wide-field auroral imager on Fengyun-3D We present the optomechanical design and development of a wide-field auroral imager (WAI) on board the satellite Fengyun-3D. The optomechanical system of the WAI features a combination of a large field of view and a single-axis scanning mechanism. The combination makes the WAI perform better than its counterparts in temporal resolution in a low Earth orbit. In-orbit tests have verified the survival of WAI in the launching vibration and space environment. It has functioned on-orbit since 2018, with a spatial resolution of ∼10km at the nadir point, at a reference height of 110 km above the ionosphere. Guo, Quanfeng; Chen, Bo; Liu, ShiJie; Song, KeFei; He, LingPing; He, Fei; Zhao, Weiguo; Wang, Zhongsu; Chen, Liheng; Shi, Guangwei; Published by: Applied Optics Published on: apr YEAR: 2022 DOI: 10.1364/AO.453949 |
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We apply a multiresolution Gaussian process model (Lattice Kriging) to combine satellite observations, ground‐based observations, and an empirical auroral model, to produce the Wu, Haonan; Tan, Xiyan; Zhang, Qiong; Huang, Whitney; Lu, Xian; Nishimura, Yukitoshi; Zhang, Yongliang; Published by: Space Weather Published on: YEAR: 2022 DOI: 10.1029/2022SW003146 |
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We use the in-situ observations of DMSP and SWARM satellites to report the changes of the topside ionospheric electron temperature during the October 2016 storm. Electron temperature in the afternoon sector dramatically increases in low latitudes in the recovery phase of the storm. Furthermore, the temperature enhancements have an obvious dependence on longitude and are mainly centralized around 100°–150°E in different satellite observations. The temperature enhancements attain more than 2,000 K at 840 km and 1,500 K at 450 km around the magnetic equator. The decrease in the electron-ion collision cooling rate, resulting from the lessened topside electron density, could not fully explain the temperature enhancement. At the same time, the electron densities in crests of the equatorial ionization anomaly are suppressed drastically at 100°–150°E, which cause a less heat conduction effect from the equatorial topside ionosphere to low altitudes via magnetic field lines and heat the topside ionospheric electron temperature. Further analysis indicates that dayside westward disturbance dynamo electric field presents a significant longitude structure and is a primary driver for the topside ionospheric temperature enhancement during the storm. Zhang, Ruilong; Liu, Libo; Ma, Han; Chen, Yiding; Le, Huijun; Yoshikawa, Akimasa; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2022 DOI: 10.1029/2022JA030278 electron temperature; equatorial topisde; Ionospheric storm; vertical drift |
| 2021 |
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Transpolar Arcs During a Prolonged Radial Interplanetary Magnetic Field Interval Transpolar arcs (TPAs) are believed to predominantly occur under northward interplanetary magnetic field (IMF) conditions with their hemispheric asymmetry controlled by the Sun-Earth (radial) component of the IMF. In this study, we present observations of TPAs that appear in both the northern and southern hemispheres even during a prolonged interval of radially oriented IMF. The Defense Meteorological Satellite Program (DMSP) F16 and the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellites observed TPAs on the dawnside polar cap in both hemispheres (one TPA structure in the southern hemisphere and two in the northern hemisphere) during an interval of nearly earthward-oriented IMF on October 29, 2005. The southern hemisphere TPA and one of the northern hemisphere TPAs are associated with electron and ion precipitation and mostly sunward plasma flow (with shears) relative to their surroundings. Meanwhile, the other TPA in the northern hemisphere is associated with an electron-only precipitation and antisunward flow relative to its surroundings. Our observations indicate the following: (a) the TPA formation is not limited to northward IMF conditions; (b) the TPAs can be located on both closed field lines rooted in the polar cap of both hemispheres and open field lines connected to the northward field lines draped over one hemisphere of the magnetopause. We believe that the TPAs presented here are the result of both indirect and direct processes of solar wind energy transfer to the high-latitude ionosphere. Park, Jong-Sun; Shi, Quan; Nowada, Motoharu; Shue, Jih-Hong; Kim, Khan-Hyuk; Lee, Dong-Hun; Zong, Qiu-Gang; Degeling, Alexander; Tian, An; Pitkänen, Timo; Zhang, Yongliang; Rae, Jonathan; Hairston, Marc; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2021 DOI: 10.1029/2021JA029197 radial IMF; solar wind-magnetosphere-ionosphere coupling; transpolar arc |
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The Ionosphere at Middle and Low Latitudes Under Geomagnetic Quiet Time of December 2019 The ionospheric electron density shows remarkable day-to-day variability due to solar radiance, geomagnetic activity and lower atmosphere forcing. In this report, we investigated the ionospheric variations at middle and low latitudes during a period under geomagnetic quiet time (Kpmax = 1.7) from November 30 to December 8, 2019. During the quiescent period, the ionosphere is not undisturbed as expected in the Asian-Australian and the American sectors. Total electron content (TEC) has multiple prominent enhancements at middle and low latitudes in the two sectors, and TEC depletions also occur repeatedly in the Asian-Australian sector. The low-latitude electric fields vary significantly, which is likely to be modulated by the notably changing tides in the mesosphere and lower thermosphere region. It is worth noting that the variations of TEC and the electric fields are not consistent in the two sectors, particularly on December 4–6. Further investigation reveals that the increase in TEC depends on altitude. The TEC enhancements are mainly contributed by the altitude below 500 km in both two sectors, which indirectly reflects that the driving sources may come from the lower atmosphere. Especially, a mid-latitude band structure continuously appears at all local times in the North American sector on December 6–8, which is also mainly contributed by the altitude below 500 km. Kuai, Jiawei; Li, Qiaoling; Zhong, Jiahao; Zhou, Xu; Liu, Libo; Yoshikawa, Akimasa; Hu, Lianhuan; Xie, Haiyong; Huang, Chaoyan; Yu, Xumin; Wan, Xin; Cui, Jun; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2021 DOI: 10.1029/2020JA028964 low-latitude electric fields; the ionosphere variations in solar minimum; the ionospheric day-to-day variations; the ionospheric disturbance; the ionospheric variations; topside ionosphere |
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Progresses and Challenges to specifying the IT system during weak storms Deng, Yue; Heelis, Roderick; Paxton, Larry; Lyons, Larry; Nishimura, Toshi; Zhang, Shunrong; Bristow, Bill; Maute, Astrid; Sheng, Cheng; Zhu, Qingyu; , others; Published by: Published on: |
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We present new measurements of the vertical density profile of the Earth s atmosphere at altitudes between 70 and 200 km, based on Earth occultations of the Crab Nebula observed with the X-ray Imaging Spectrometer onboard Suzaku and the hard X-ray Imager onboard Hitomi. X-ray spectral variation due to the atmospheric absorption is used to derive tangential column densities of the absorbing species, that is, N and O including atoms and molecules, along the line of sight. The tangential column densities are then inverted to obtain the atmospheric number density. The data from 219 occultation scans at low latitudes in both hemispheres from September 15, 2005 to March 26, 2016 are analyzed to generate a single, highly averaged (in both space and time) vertical density profile. The density profile is in good agreement with the Naval-Research-Laboratory s-Mass-Spectrometer-Incoherent-Scatter-Radar-Extended (NRLMSISE-00) model, except for the altitude range of 70–110 km, where the measured density is ∼50\% smaller than the model. Such a deviation is consistent with the recent measurement with the SABER aboard the TIMED satellite (Cheng et al., 2020, https://doi.org/10.3390/atmos11040341). Given that the NRLMSISE-00 model was constructed some time ago, the density decline could be due to the radiative cooling/contracting of the upper atmosphere as a result of greenhouse warming in the troposphere. However, we cannot rule out a possibility that the NRL model is simply imperfect in this region. We also present future prospects for the upcoming Japan-US X-ray astronomy satellite, X-Ray Imaging and Spectroscopy Mission (XRISM), which will allow us to measure atmospheric composition with unprecedented spectral resolution of ΔE ∼ 5 eV in 0.3–12 keV. Katsuda, Satoru; Fujiwara, Hitoshi; Ishisaki, Yoshitaka; Yoshitomo, Maeda; Mori, Koji; Motizuki, Yuko; Sato, Kosuke; Tashiro, Makoto; Terada, Yukikatsu; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2021 DOI: 10.1029/2020JA028886 Crab Nebula; Hitomi; occultation; Suzaku; upper atmosphere; X-rays |
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We present new measurements of the vertical density profile of the Earth s atmosphere at altitudes between 70 and 200 km, based on Earth occultations of the Crab Nebula observed with the X-ray Imaging Spectrometer onboard Suzaku and the hard X-ray Imager onboard Hitomi. X-ray spectral variation due to the atmospheric absorption is used to derive tangential column densities of the absorbing species, that is, N and O including atoms and molecules, along the line of sight. The tangential column densities are then inverted to obtain the atmospheric number density. The data from 219 occultation scans at low latitudes in both hemispheres from September 15, 2005 to March 26, 2016 are analyzed to generate a single, highly averaged (in both space and time) vertical density profile. The density profile is in good agreement with the Naval-Research-Laboratory s-Mass-Spectrometer-Incoherent-Scatter-Radar-Extended (NRLMSISE-00) model, except for the altitude range of 70–110 km, where the measured density is ∼50\% smaller than the model. Such a deviation is consistent with the recent measurement with the SABER aboard the TIMED satellite (Cheng et al., 2020, https://doi.org/10.3390/atmos11040341). Given that the NRLMSISE-00 model was constructed some time ago, the density decline could be due to the radiative cooling/contracting of the upper atmosphere as a result of greenhouse warming in the troposphere. However, we cannot rule out a possibility that the NRL model is simply imperfect in this region. We also present future prospects for the upcoming Japan-US X-ray astronomy satellite, X-Ray Imaging and Spectroscopy Mission (XRISM), which will allow us to measure atmospheric composition with unprecedented spectral resolution of ΔE ∼ 5 eV in 0.3–12 keV. Katsuda, Satoru; Fujiwara, Hitoshi; Ishisaki, Yoshitaka; Yoshitomo, Maeda; Mori, Koji; Motizuki, Yuko; Sato, Kosuke; Tashiro, Makoto; Terada, Yukikatsu; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2021 DOI: 10.1029/2020JA028886 Crab Nebula; Hitomi; occultation; Suzaku; upper atmosphere; X-rays |
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We present new measurements of the vertical density profile of the Earth s atmosphere at altitudes between 70 and 200 km, based on Earth occultations of the Crab Nebula observed with the X-ray Imaging Spectrometer onboard Suzaku and the hard X-ray Imager onboard Hitomi. X-ray spectral variation due to the atmospheric absorption is used to derive tangential column densities of the absorbing species, that is, N and O including atoms and molecules, along the line of sight. The tangential column densities are then inverted to obtain the atmospheric number density. The data from 219 occultation scans at low latitudes in both hemispheres from September 15, 2005 to March 26, 2016 are analyzed to generate a single, highly averaged (in both space and time) vertical density profile. The density profile is in good agreement with the Naval-Research-Laboratory s-Mass-Spectrometer-Incoherent-Scatter-Radar-Extended (NRLMSISE-00) model, except for the altitude range of 70–110 km, where the measured density is ∼50\% smaller than the model. Such a deviation is consistent with the recent measurement with the SABER aboard the TIMED satellite (Cheng et al., 2020, https://doi.org/10.3390/atmos11040341). Given that the NRLMSISE-00 model was constructed some time ago, the density decline could be due to the radiative cooling/contracting of the upper atmosphere as a result of greenhouse warming in the troposphere. However, we cannot rule out a possibility that the NRL model is simply imperfect in this region. We also present future prospects for the upcoming Japan-US X-ray astronomy satellite, X-Ray Imaging and Spectroscopy Mission (XRISM), which will allow us to measure atmospheric composition with unprecedented spectral resolution of ΔE ∼ 5 eV in 0.3–12 keV. Katsuda, Satoru; Fujiwara, Hitoshi; Ishisaki, Yoshitaka; Yoshitomo, Maeda; Mori, Koji; Motizuki, Yuko; Sato, Kosuke; Tashiro, Makoto; Terada, Yukikatsu; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2021 DOI: 10.1029/2020JA028886 Crab Nebula; Hitomi; occultation; Suzaku; upper atmosphere; X-rays |
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This paper reports that plasma density depletions appearing at middle latitudes near sunrise survived until afternoon on 29 May 2017 during the recovery phase of a geomagnetic storm. By analyzing GPS data collected in Japan, we investigate temporal variations in the horizontal two-dimensional distribution of total electron content (TEC) during the geomagnetic storm. The SYM-H index reached −142 nT around 08 UT on 28 May 2017. TEC depletions extending up to approximately 38°N along the meridional direction appeared over Japan around 05 LT (LT = UT + 9 hours) on 29 May 2017, when TEC rapidly increased at sunrise due to the solar extreme ultraviolet (EUV) radiation. The TEC depletions appeared sequentially over Japan for approximately 8 hours in sunlit conditions. At 06 LT on 29 May, when the plasma depletions first appeared over Japan, the background TEC was enhanced to approximately 17 TECU, and then decreased to approximately 80\% of the TEC typical of magnetically quiet conditions. We conclude that this temporal variation of background plasma density in the ionosphere was responsible for the persistence of these plasma depletions for so long in daytime. By using the Naval Research Laboratory: Sami2 is Another Model of the Ionosphere (SAMI2), we have evaluated how plasma production and ambipolar diffusion along the magnetic field may affect the rate of plasma depletion disappearance. Simulation shows that the plasma density increases at the time of plasma depletion appearance; subsequent decreases in the plasma density appear to be responsible for the long-lasting persistence of plasma depletions during daytime. The plasma density depletion in the top side ionosphere is not filled by the plasma generated by the solar EUV productions because plasma production occurs mainly at the bottom side of the ionosphere. Otsuka, Yuichi; Shinbori, Atsuki; Sori, Takuya; Tsugawa, Takuya; Nishioka, Michi; Huba, Joseph; Published by: Earth and Planetary Physics Published on: YEAR: 2021 DOI: 10.26464/epp2021046 Ionosphere; GPS; ionospheric irregularity; plasma bubble; SAMI2 |
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This paper reports that plasma density depletions appearing at middle latitudes near sunrise survived until afternoon on 29 May 2017 during the recovery phase of a geomagnetic storm. By analyzing GPS data collected in Japan, we investigate temporal variations in the horizontal two-dimensional distribution of total electron content (TEC) during the geomagnetic storm. The SYM-H index reached −142 nT around 08 UT on 28 May 2017. TEC depletions extending up to approximately 38°N along the meridional direction appeared over Japan around 05 LT (LT = UT + 9 hours) on 29 May 2017, when TEC rapidly increased at sunrise due to the solar extreme ultraviolet (EUV) radiation. The TEC depletions appeared sequentially over Japan for approximately 8 hours in sunlit conditions. At 06 LT on 29 May, when the plasma depletions first appeared over Japan, the background TEC was enhanced to approximately 17 TECU, and then decreased to approximately 80\% of the TEC typical of magnetically quiet conditions. We conclude that this temporal variation of background plasma density in the ionosphere was responsible for the persistence of these plasma depletions for so long in daytime. By using the Naval Research Laboratory: Sami2 is Another Model of the Ionosphere (SAMI2), we have evaluated how plasma production and ambipolar diffusion along the magnetic field may affect the rate of plasma depletion disappearance. Simulation shows that the plasma density increases at the time of plasma depletion appearance; subsequent decreases in the plasma density appear to be responsible for the long-lasting persistence of plasma depletions during daytime. The plasma density depletion in the top side ionosphere is not filled by the plasma generated by the solar EUV productions because plasma production occurs mainly at the bottom side of the ionosphere. Otsuka, Yuichi; Shinbori, Atsuki; Sori, Takuya; Tsugawa, Takuya; Nishioka, Michi; Huba, Joseph; Published by: Earth and Planetary Physics Published on: YEAR: 2021 DOI: 10.26464/epp2021046 Ionosphere; GPS; ionospheric irregularity; plasma bubble; SAMI2 |
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Recent attention has been given to mesoscale phenomena across geospace (∼10 s km to 500 km in the ionosphere or ∼0.5 RE to several RE in the magnetosphere), as their contributions to the system global response are important yet remain uncharacterized mostly due to limitations in data resolution and coverage as well as in computational power. As data and models improve, it becomes increasingly valuable to advance understanding of the role of mesoscale phenomena contributions—specifically, in magnetosphere-ionosphere coupling. This paper describes a new method that utilizes the 2D array of Time History of Events and Macroscale Interactions during Substorms (THEMIS) white-light all-sky-imagers (ASI), in conjunction with meridian scanning photometers, to estimate the auroral scale sizes of intense precipitating energy fluxes and the associated Hall conductances. As an example of the technique, we investigated the role of precipitated energy flux and average energy on mesoscales as contrasted to large-scales for two back-to-back substorms, finding that mesoscale aurora contributes up to ∼80\% (∼60\%) of the total energy flux immediately after onset during the early expansion phase of the first (second) substorm, and continues to contribute ∼30–55\% throughout the remainder of the substorm. The average energy estimated from the ASI mosaic field of view also peaked during the initial expansion phase. Using the measured energy flux and tables produced from the Boltzmann Three Constituent (B3C) auroral transport code (Strickland et al., 1976; 1993), we also estimated the 2D Hall conductance and compared it to Poker Flat Incoherent Scatter Radar conductance values, finding good agreement for both discrete and diffuse aurora. Gabrielse, Christine; Nishimura, Toshi; Chen, Margaret; Hecht, James; Kaeppler, Stephen; Gillies, Megan; Reimer, Ashton; Lyons, Larry; Deng, Yue; Donovan, Eric; Evans, Scott; Published by: Frontiers in Physics Published on: |
| 2020 |
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This chapter reviews fundamental properties and recent advances of diffuse and pulsating aurora. Diffuse and pulsating aurora often occurs on closed field lines and involves energetic electron precipitation by wave-particle interaction. After summarizing the definition, large-scale morphology, types of pulsation, and driving processes, we review observation techniques, occurrence, duration, altitude, evolution, small-scale structures, fast modulation, relation to high-energy precipitation, the role of ECH waves, reflected and secondary electrons, ionosphere dynamics, and simulation of wave-particle interaction. Finally we discuss open questions of diffuse and pulsating aurora. Nishimura, Yukitoshi; Lessard, Marc; Katoh, Yuto; Miyoshi, Yoshizumi; Grono, Eric; Partamies, Noora; Sivadas, Nithin; Hosokawa, Keisuke; Fukizawa, Mizuki; Samara, Marilia; Michell, Robert; Kataoka, Ryuho; Sakanoi, Takeshi; Whiter, Daniel; Oyama, Shin-ichiro; Ogawa, Yasunobu; Kurita, Satoshi; Published by: Space Science Reviews Published on: 01/2020 YEAR: 2020 DOI: 10.1007/s11214-019-0629-3 |
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This chapter reviews fundamental properties and recent advances of diffuse and pulsating aurora. Diffuse and pulsating aurora often occurs on closed field lines and involves energetic electron precipitation by wave-particle interaction. After summarizing the definition, large-scale morphology, types of pulsation, and driving processes, we review observation techniques, occurrence, duration, altitude, evolution, small-scale structures, fast modulation, relation to high-energy precipitation, the role of ECH waves, reflected and secondary electrons, ionosphere dynamics, and simulation of wave-particle interaction. Finally we discuss open questions of diffuse and pulsating aurora. Nishimura, Yukitoshi; Lessard, Marc; Katoh, Yuto; Miyoshi, Yoshizumi; Grono, Eric; Partamies, Noora; Sivadas, Nithin; Hosokawa, Keisuke; Fukizawa, Mizuki; Samara, Marilia; Michell, Robert; Kataoka, Ryuho; Sakanoi, Takeshi; Whiter, Daniel; Oyama, Shin-ichiro; Ogawa, Yasunobu; Kurita, Satoshi; Published by: Space Science Reviews Published on: 01/2020 YEAR: 2020 DOI: 10.1007/s11214-019-0629-3 |
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Nishimura, Y; Yang, J; Weygand, JM; Wang, W; Kosar, B; Donovan, EF; , Angelopoulos; Paxton, LJ; Nishitani, N; Published by: Journal of Geophysical Research: Space Physics Published on: |
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Nishimura, Y; Yang, J; Weygand, JM; Wang, W; Kosar, B; Donovan, EF; , Angelopoulos; Paxton, LJ; Nishitani, N; Published by: Journal of Geophysical Research: Space Physics Published on: |
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Unprecedented hemispheric asymmetries during a surprise ionospheric storm: A game of drivers Astafyeva, Elvira; Bagiya, Mala; Förster, Matthias; Nishitani, Nozomu; Published by: Journal of Geophysical Research: Space Physics Published on: |
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Li, Qiaoling; Huang, Fuqing; Zhong, Jiahao; Zhang, Ruilong; Kuai, Jiawei; Lei, Jiuhou; Liu, Libo; Ren, Dexin; Ma, Han; Yoshikawa, Akimasa; , others; Published by: Journal of geophysical research: space physics Published on: |
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Nishimura, Y; Yang, J; Weygand, JM; Wang, W; Kosar, B; Donovan, EF; , Angelopoulos; Paxton, LJ; Nishitani, N; Published by: Journal of Geophysical Research: Space Physics Published on: |
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Nishimura, Y; Yang, J; Weygand, JM; Wang, W; Kosar, B; Donovan, EF; , Angelopoulos; Paxton, LJ; Nishitani, N; Published by: Journal of Geophysical Research: Space Physics Published on: |
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This paper focuses on unique aspects of the ionospheric response at conjugate locations over Europe and South Africa during the 7–8 September 2017 geomagnetic storm including Habarulema, John; Katamzi-Joseph, Zama; a, Dalia; Nndanganeni, Rendani; Matamba, Tshimangadzo; Tshisaphungo, Mpho; Buchert, Stephan; Kosch, Michael; Lotz, Stefan; Cilliers, Pierre; , others; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2020 DOI: 10.1029/2020JA028307 |
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Physical processes of meso-scale, dynamic auroral forms Meso-scale auroral forms, such as poleward boundary intensifications, streamers, omega bands, beads and giant undulations, are manifestations of dynamic processes in the magnetosphere driven, to a large part, by plasma instabilities in the magnetotail. New observations from ground- and space-based instrumentation and theoretical treatments are giving us a clearer view of some of the physical processes behind these auroral forms. However, questions remain as to how some of these observations should be interpreted, given uncertainties in mapping auroral features to locations in the magnetotatil and due to the significant overlap in the results from a variety of models of different plasma instabilities. We provide an overview of recent results in the field and seek to clarify some of the remaining questions with regards to what drives some of the largest and most dynamic auroral forms. Forsyth, C; Sergeev, VA; Henderson, MG; Nishimura, Y; Gallardo-Lacourt, B; Published by: Space Science Reviews Published on: YEAR: 2020 DOI: 10.1007/s11214-020-00665-y |
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The development of an ionospheric storm-time index for the South African region This thesis presents the development of a regional ionospheric storm-time model which forms the foundation of an index to provide a quick view of the ionospheric storm effects over Published by: Published on: |
| 2019 |
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Dayside aurora is related to processes in the dayside magnetosphere and especially at the dayside magnetopause. A number of dayside aurora phenomena are driven by reconnection between the solar wind interplanetary magnetic field and the Earth\textquoterights internal magnetic field at the magnetopause. We summarize the properties and origin of aurora at the cusp foot point, High Latitude Dayside Aurora (HiLDA), Poleward Moving Auroral Forms (PMAFs), aurora related to traveling convection vortices (TCV), and throat aurora. Furthermore we discuss dayside diffuse aurora, morning side diffuse aurora spots, and shock aurora. Frey, Harald; Han, Desheng; Kataoka, Ryuho; Lessard, Marc; Milan, Stephen; Nishimura, Yukitoshi; Strangeway, Robert; Zou, Ying; Published by: Space Science Reviews Published on: 11/2019 YEAR: 2019 DOI: 10.1007/s11214-019-0617-7 |
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The characteristics of global electron density variations in the ionosphere during a geomagnetic storm on November 7 and 8, 2004, were investigated using total electron content (TEC) obtained from the global navigation satellite system (GNSS). The regions of enhanced TEC over North America, Europe, and Japan first appeared in the mid-latitude regions. The TEC enhancements over North America showed a rapid longitudinal expansion and reached a wide longitudinal extent during the initial and main phases of the geomagnetic storm. TEC enhancements were simultaneously observed in both North America and Japan at 05:00 UT on November 8. Observation data from the Defense Meteorological Satellite Program showed a slight enhancement of electron density at 850 km below the equatorward boundary of the mid-latitude trough (45\textendash48\textdegreeN in geomagnetic latitude) over the Pacific Ocean. This electron density variation may correspond to the TEC enhancements observed in both Japan and North America. These results imply that an enhanced TEC region existed between North America and Japan. The TEC enhancement in Japan appeared with a magnetic conjugacy in the Southern hemisphere, indicating one of the characteristics of storm-enhanced density (SED). Moreover, TEC enhancements simultaneously appeared from Japan to Central Asia at 11:00 UT on November 8, corresponding to the early recovery phase of the geomagnetic storm. From the above results, it is suggested that SED phenomena can be simultaneously generated over a wide longitudinal width (~100\textdegree). The longitudinal extent of this SED event is 2.5\textendash5.0 times longer than those reported by previous studies. Sori, T.; Shinbori, A.; Otsuka, Y.; Tsugawa, T.; Nishioka, M.; Published by: Journal of Geophysical Research: Space Physics Published on: 10/2019 YEAR: 2019 DOI: 10.1029/2019JA026713 |
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The characteristics of global electron density variations in the ionosphere during a geomagnetic storm on November 7 and 8, 2004, were investigated using total electron content (TEC) obtained from the global navigation satellite system (GNSS). The regions of enhanced TEC over North America, Europe, and Japan first appeared in the mid-latitude regions. The TEC enhancements over North America showed a rapid longitudinal expansion and reached a wide longitudinal extent during the initial and main phases of the geomagnetic storm. TEC enhancements were simultaneously observed in both North America and Japan at 05:00 UT on November 8. Observation data from the Defense Meteorological Satellite Program showed a slight enhancement of electron density at 850 km below the equatorward boundary of the mid-latitude trough (45\textendash48\textdegreeN in geomagnetic latitude) over the Pacific Ocean. This electron density variation may correspond to the TEC enhancements observed in both Japan and North America. These results imply that an enhanced TEC region existed between North America and Japan. The TEC enhancement in Japan appeared with a magnetic conjugacy in the Southern hemisphere, indicating one of the characteristics of storm-enhanced density (SED). Moreover, TEC enhancements simultaneously appeared from Japan to Central Asia at 11:00 UT on November 8, corresponding to the early recovery phase of the geomagnetic storm. From the above results, it is suggested that SED phenomena can be simultaneously generated over a wide longitudinal width (~100\textdegree). The longitudinal extent of this SED event is 2.5\textendash5.0 times longer than those reported by previous studies. Sori, T.; Shinbori, A.; Otsuka, Y.; Tsugawa, T.; Nishioka, M.; Published by: Journal of Geophysical Research: Space Physics Published on: 10/2019 YEAR: 2019 DOI: 10.1029/2019JA026713 |
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Measurements of the limiting escape rate of atomic hydrogen (H) atoms at Earth, and the relative significance of thermal evaporation and non-thermal escape mechanisms, such as charge exchange and polar wind, have long been lacking. Our recent development of sophisticated radiative transport analysis techniques now enables the reliable interpretation of remotely-sensed measurements of optically-thick H emission, such as those acquired along the Earth\textquoterights limb by the Global Ultraviolet Imager (GUVI) onboard the NASA TIMED spacecraft, in terms of physical parameters such as exobase density and, crucially, vertical diffusive flux. In this work, we present results from a systematic investigation of H Lyα emission measured by TIMED/GUVI along the Earth\textquoterights dayside limb from 2002-2007, which we use to derive the vertical H flux and associated density distribution from 250 km out to 1 earth radius. Our analysis reveals that the vertical flux of thermospheric H is nearly constant ver a large range of solar activity and typically exceeds the calculated thermal evaporative flux, suggesting that terrestrial H escape is indeed limited by its vertical diffusion. The excess supply of H atoms to the exobase associated with large observed vertical fluxes requires that non-thermal escape mechanisms be operative for steady-state continuity balance. We find that such non-thermal processes are a particularly significant component of total H escape during low solar activity, when thermal evaporation is weakest. Joshi, P.P.; Phal, Y.D.; Waldrop, L.S.; Published by: Journal of Geophysical Research: Space Physics Published on: 10/2019 YEAR: 2019 DOI: 10.1029/2019JA027057 |
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Wide-field auroral imager onboard the Fengyun satellite The newly launched Fengyun-3D (FY-3D) satellite carried a wide-field auroral imager (WAI) that was developed by Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences (CIOMP), which will provide a large field of view (FOV), high spatial resolution, and broadband ultraviolet images of the aurora and the ionosphere by imaging the N2 LBH bands of emissions. The WAI consists of two identical cameras, each with an FOV of 68\textdegree in the along-track direction and 10\textdegree in the cross-track direction. The two cameras are tilted relative to each other to cover a fan-shaped field of size 130\textdegree \texttimes 10\textdegree. Each camera consists of an unobstructed four-mirror anastigmatic optical system, a BaF2 filter, and a photon-counting imaging detector. The spatial resolution of WAI is ~10 km at the nadir point at a reference height of 110 km above the Earth\textquoterights surface. The sensitivity is \>0.01 counts s-1 Rayleigh-1 pixel-1 (140\textendash180 nm) for both cameras, which is sufficient for mapping the boundaries and the fine structures of the auroral oval during storms/substorms. Based on the tests and calibrations that were conducted prior to launch, the data processing algorithm includes photon signal decoding, geometric distortion correction, photometric correction, flat-field correction, line-of-sight projection and correction, and normalization between the two cameras. Preliminarily processed images are compared with DMSP SSUSI images. The agreement between the images that were captured by two instruments demonstrates that the WAI and the data processing algorithm operate normally and can provide high-quality scientific data for future studies on auroral dynamics. Zhang, Xiao-Xin; Chen, Bo; He, Fei; Song, Ke-Fei; He, Ling-Ping; Liu, Shi-Jie; Guo, Quan-Feng; Li, Jia-Wei; Wang, Xiao-Dong; Zhang, Hong-Ji; Wang, Hai-Feng; Han, Zhen-Wei; Sun, Liang; Zhang, Pei-Jie; Dai, Shuang; Ding, Guang-Xing; Chen, Li-Heng; Wang, Zhong-Su; Shi, Guang-Wei; Zhang, Xin; Yu, Chao; Yang, Zhong-Dong; Zhang, Peng; Wang, Jin-Song; Published by: Light: Science \& Applications Published on: 05/2019 YEAR: 2019 DOI: 10.1038/s41377-019-0157-7 |
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Nishimura, Toshi; Paxton, Larry; Lyons, Larry; Erickson, Philip; Published by: Published on: |
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Sori, T; Shinbori, A; Otsuka, Y; Tsugawa, T; Nishioka, M; Published by: Journal of Geophysical Research: Space Physics Published on: |
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Sori, T; Shinbori, A; Otsuka, Y; Tsugawa, T; Nishioka, M; Published by: Journal of Geophysical Research: Space Physics Published on: |
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Earth's transpolar arc originated simultaneously from dayside and nightside. Transpolar arc/theta aurora have been observed and modeled for more than thirty years. Most of the proposed models (more than 10 in total) predict one continuous band for a Published by: Published on: |
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The GUVI data are provided through support from the NASA MO&DA program. The GUVI instrument was designed and built by The Aerospace Corporation and The Johns Hopkins Padokhin, AM; Tereshin, NA; Yasyukevich, Yu; Andreeva, ES; Nazarenko, MO; Yasyukevich, AS; Kozlovtseva, EA; Kurbatov, GA; Published by: Advances in Space Research Published on: YEAR: 2019 DOI: 10.1016/j.asr.2018.08.001 |
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Solar wind entry into the lobe and the related polar cap auroral arc growing Published by: Published on: |
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Review of the accomplishments of mid-latitude Super Dual Auroral Radar Network (SuperDARN) HF radars The Super Dual Auroral Radar Network (SuperDARN) is a network of high-frequency (HF) radars located in the high- and mid-latitude regions of both hemispheres that is operated under international cooperation. The network was originally designed for monitoring the dynamics of the ionosphere and upper atmosphere in the high-latitude regions. However, over the last approximately 15 years, SuperDARN has expanded into the mid-latitude regions. With radar coverage that now extends continuously from auroral to sub-auroral and mid-latitudes, a wide variety of new scientific findings have been obtained. In this paper, the background of mid-latitude SuperDARN is presented at first. Then, the accomplishments made with mid-latitude SuperDARN radars are reviewed in five specified scientific and technical areas: convection, ionospheric irregularities, HF propagation analysis, ion-neutral interactions, and magnetohydrodynamic (MHD) waves. Finally, the present status of mid-latitude SuperDARN is updated and directions for future research are discussed. Nishitani, Nozomu; Ruohoniemi, John; Lester, Mark; Baker, Joseph; Koustov, Alexandre; Shepherd, Simon; Chisham, Gareth; Hori, Tomoaki; Thomas, Evan; Makarevich, Roman; , others; Published by: Progress in Earth and Planetary Science Published on: YEAR: 2019 DOI: 10.1186/s40645-019-0270-5 |
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Park, Jong-Sun; Shi, Quanqi; Nowada, Motoharu; Shue, Jih-Hong; Kim, Khan-Hyuk; Lee, Dong-Hun; Zong, Qiugang; Degeling, Alexander; Tian, Anmin; Pitkänen, Timo; , others; Published by: Published on: |
| 2018 |
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Observation of equatorial plasma bubbles by the airglow imager on ISS-IMAP Using 630 nm airglow data observed by an airglow imager on the International Space Station (ISS), the occurrence of equatorial plasma bubbles (EPBs) is studied. In order to examine the physical mechanisms in the boundary region between the Earth and the outer space, an ionosphere, mesosphere, upper atmosphere, and plasmasphere mapping (IMAP) mission had been conducted onboard the ISS since October 2012. The visible light and infrared spectrum imager (VISI) is utilized in the ISS-IMAP mission for nadir-looking observation of the earth\textquoterights atmospheric airglow. In this study, we automatically select EPBs according to the criterion for extracting the tilted dark lines from VISI data. Using the selected events, the dependence of the occurrence rate of EPBs is examined. There is no other report of the occurrence rate of EPBs using downward-looking visible airglow data (630 nm). In this result, the occurrence rate is high at all longitudes in the equinoctial seasons. In the solstice seasons, in contrast, the occurrence rate is very small especially in the Pacific and American sectors. This result is basically consistent with previous studies, e.g., those determined by plasma density data on DMSP satellites.During the June solstice in 2013, EPBs were observed in association with geomagnetic storms that occurred due to a southward turning of the IMF Bz. Using these events, we examined the storm-time features of the occurrence of EPBs in the Pacific-American sectors during the June solstice. In these sectors, where the occurrence rate of EPBs is very small during solstice seasons, some EPBs were observed in the peak and recovery phases of the storms. This result shows that the prompt penetration of electric fields causes the development of EPBs, in the data we analyzed, the geomagnetic storms did not inhibit the generation of EPB in the Pacific\textendashAmerican sectors. Nakata, Hiroyuki; Takahashi, Akira; Takano, Toshiaki; Saito, Akinori; Sakanoi, Takeshi; Published by: Progress in Earth and Planetary Science Published on: 12/2018 YEAR: 2018 DOI: 10.1186/s40645-018-0227-0 |
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Lyons, LR; Gallardo-Lacourt, B; Zou, Y; Nishimura, Y; Anderson, P; , Angelopoulos; Donovan, EF; Ruohoniemi, JM; Mitchell, E; Paxton, LJ; , others; Published by: Journal of Atmospheric and Solar-Terrestrial Physics Published on: |
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| 2017 |
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Polekh, N.; Zolotukhina, N.; Kurkin, V.; Zherebtsov, G.; Shi, J.; Wang, G.; Wang, Z.; Published by: Advances in Space Research Published on: 12/2017 YEAR: 2017 DOI: 10.1016/j.asr.2017.09.030 |
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Dynamics of ionospheric disturbances during the 17—19 March 2015 geomagnetic storm over East Asia Based on vertical sounding data from nine ionosondes located at 19–66N, 100–130E we investigated the latitude-temporal dynamics of ionospheric disturbances during the 17–19 Polekh, N; Zolotukhina, N; , Kurkin; Zherebtsov, G; Shi, J; Wang, G; Wang, Z; Published by: Advances in Space Research Published on: YEAR: 2017 DOI: 10.1016/j.asr.2017.09.030 |
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QUASI-BIENNIAL VARIATIONS IN IONOSPHERIC TIDAL/SPW AMPLITUDES: OBSERVATIONS AND MODELING Loren, Cheewei; Yan-Yi, Sun; Jack, Chieh; Shih-Han, Chien; Rung, Tsai-Lin; Jia, Yue; Published by: Published on: |
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Driving of Dramatic Geomagnetic Activity by Enhancement of Meso-Scale Polar-cap Flows Lyons, Larry; Gallardo-Lacourt, Bea; Zou, Ying; Nishimura, Yukitoshi; Anderson, Phillip; Angelopoulos, VASSILIS; Ruohoniemi, Michael; Mitchell, Elizabeth; Paxton, Larry; Nishitani, Nozomu; Published by: Published on: |
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Driving of Dramatic Geomagnetic Activity by Enhancement of Meso-Scale Polar-cap Flows Lyons, Larry; Gallardo-Lacourt, Bea; Zou, Ying; Nishimura, Yukitoshi; Anderson, Phillip; Angelopoulos, VASSILIS; Ruohoniemi, Michael; Mitchell, Elizabeth; Paxton, Larry; Nishitani, Nozomu; Published by: Published on: |
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Analysis and design of the ultraviolet warning optical system based on interference imaging Ultraviolet warning technology is one of the important methods for missile warning. It provides a very effective way to detect the target for missile approaching alarm. With the development of modern technology, especially the development of information technology at high speed, the ultraviolet early warning system plays an increasingly important role. Compared to infrared warning, the ultraviolet warning has high efficiency and low false alarm rate. In the modern warfare, how to detect the threats earlier, prevent and reduce the attack of precision-guided missile has become a new challenge of missile warning technology. Because the ultraviolet warning technology has high environmental adaptability, the low false alarm rate, small volume and other advantages, in the military field applications it has been developed rapidly. For the ultraviolet warning system, the optimal working waveband is 250 nm ~280 nm (Solar Blind UV) due to the strong absorption of ozone layer. According to current application demands for solar blind ultraviolet detection and warning, this paper proposes ultraviolet warning optical system based on interference imaging, which covers solar blind ultraviolet (250nm-280nm) and dual field. This structure includes a primary optical system, an ultraviolet reflector array, an ultraviolet imaging system and an ultraviolet interference imaging system. It makes use of an ultraviolet beam-splitter to achieve the separation of two optical systems. According to the detector and the corresponding application needs of two visual field of the optical system, the calculation and optical system design were completed. After the design, the MTF of the two optical system is more than 0.8@39lp/mm.A single pixel energy concentration is greater than 80\%. Wencong, Wang; Jin, Dong-dong; Chu, Xin-bo; Shi, Yu-feng; Song, Juan; Liu, Jin-sheng; Shao, Si-pei; Hu, Hui-jun; Xiao, Ting; Published by: Published on: YEAR: 2017 DOI: 10.1117/12.2285832 |
| 2016 |
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With the development of modern technology, especially the development of information technology at high speed, the ultraviolet early warning system plays an increasingly important role. In the modern warfare, how to detect the threats earlier, prevent and reduce the attack of precision-guided missile has become a new challenge. Because the ultraviolet warning technology has high environmental adaptability, the low false alarm rate, small volume and other advantages, in the military field applications it has been developed rapidly. According to current application demands for solar blind ultraviolet detection and warning, this paper proposes a reconnaissance and early-warning optical system, which covers solar blind ultraviolet (250nm-280nm) and dual field. This structure takes advantage of a narrow field of view and long focal length optical system to achieve the target object detection, uses wide-field and short focal length optical system to achieve early warning of the target object. It makes use of an ultraviolet beam-splitter to achieve the separation of two optical systems. According to the detector and the corresponding application needs of two visual field of the optical system, the calculation and optical system design were completed. After the design, the MTF of the two optical system is more than 0.8@39lp/mm. A single pixel energy concentration is greater than 80\%. Wang, Wen-cong; Jin, Dong-dong; Shao, Fei; Hu, Hui-jun; Shi, Yu-feng; Song, Juan; Zhang, Yu-tu; Yong, Liu; Published by: Published on: YEAR: 2016 DOI: 10.1117/12.2236440 |
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Romanova, Elena; Zherebtsov, Gelii; Polekh, Nelya; Wang, Xiao; Wang, Guojun; Zolotukhina, Nina; Shi, Jiankui; Published by: 41st COSPAR Scientific Assembly Published on: |