International Journal of Geomagnetism and Aeronomy最新文献

Estimation of parameters of ionospheric wave disturbances on the basis of measurements of the Doppler shift of signal frequency of low-orbiting satellites 基于低轨道卫星信号频率多普勒频移测量的电离层波扰动参数估算

International Journal of Geomagnetism and Aeronomy Pub Date : 2008-12-18 DOI: 10.1029/2006GI000147

T. V. Chmyga, V. F. Pushin, O. F. Tyrnov, O. V. Alexanova

{"title":"Estimation of parameters of ionospheric wave disturbances on the basis of measurements of the Doppler shift of signal frequency of low-orbiting satellites","authors":"T. V. Chmyga, V. F. Pushin, O. F. Tyrnov, O. V. Alexanova","doi":"10.1029/2006GI000147","DOIUrl":"https://doi.org/10.1029/2006GI000147","url":null,"abstract":"[1] Calculations of the Doppler shift of the frequency (DSF) of a UHF signal under given models of a wave disturbance (WD), undisturbed medium, and particular orbits of low-orbiting (LO) satellites showed that there is an angle-of-approach effect. On the basis of the angle-of-approach effect a method of estimation of model parameters of medium-scale WD on the basis of measurements of DSF of signals from LO satellites in one observation point is developed. A trend in DSF variations is detected in the initial time series. Using this trend, the global model of the undisturbed ionosphere is corrected. For the parameters estimation, calculated trajectory parameters of the satellite and recordings of DSF variations are used. The numerical experiment carried out demonstrates the efficiency of the method developed. The method was tested at a series of DSF registrations received from LO satellites of the Tsykada type in 2002–2004. The analysis of DSF registrations showed that at high zenith angles for the orbits close to the central ones, WD disturbances with a vertical component are often observed. In such cases, the vertical wavelength can reach 140 km. For horizontal WD, the estimates of the wavelength give values >100 km. The range of variations of the maximum relative disturbance of the electron concentration is 1–7%.","PeriodicalId":135868,"journal":{"name":"International Journal of Geomagnetism and Aeronomy","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129591842","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}

引用次数: 0

Formation of negative disturbances in the topside ionosphere during solar flares 太阳耀斑期间上层电离层负扰动的形成

International Journal of Geomagnetism and Aeronomy Pub Date : 2008-09-09 DOI: 10.1029/2006GI000157

L. A. Leonovich, A. Taschilin

{"title":"Formation of negative disturbances in the topside ionosphere during solar flares","authors":"L. A. Leonovich, A. Taschilin","doi":"10.1029/2006GI000157","DOIUrl":"https://doi.org/10.1029/2006GI000157","url":null,"abstract":"[1] The results of studies of the ionospheric response to solar flares are presented. The results are based on the observations of GPS signals and at incoherent scatter radars and on theoretical calculations. Analyzing the GPS data, the method based on a partial “shadowing” of the atmosphere by the Earth was used. This method made it possible to estimate the value of the electron content variations in the topside ionosphere during the solar flare on 14 July 2000. We obtained that according to the GPS data at altitudes of the topside ionosphere (h > 300 km) a flare is able to cause a decrease of the electron content. Similar eects of formation of a negative disturbance in the ionospheric region were observed also during the solar flares on 21 and 23 May 1967 by the Arecibo radar. Using the theoretical model of ionosphere‐plasmasphere interaction, we study in this paper the mechanism of formation of negative disturbances in the topside ionosphere during solar flares. It is shown that the intense transport of O + ions into the above-situated plasma caused by a sharp increase in the ion production rate and thermal expansion of the ionospheric plasma is a cause of the formation of the negative disturbance in the electron concentration in the topside ionosphere. INDEX TERMS: 2481 Ionosphere: Topside ionosphere; 2435 Ionosphere: Ionospheric disturbances; 2467 Ionosphere: Plasma temperature and density; KEYWORDS: Electron content variations; solar flare; GPS receivers network; Arecibo IS installation.","PeriodicalId":135868,"journal":{"name":"International Journal of Geomagnetism and Aeronomy","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131283816","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}

引用次数: 1

Comparison and validation studies related to the modeling ionospheric convection and the European incoherent scatter observations in the polar cap 电离层对流模拟与极帽欧洲非相干散射观测的比较与验证研究

International Journal of Geomagnetism and Aeronomy Pub Date : 2008-03-13 DOI: 10.1029/2007GI000169

R. Lukianova, A. Kozlovsky, T. Turunen

{"title":"Comparison and validation studies related to the modeling ionospheric convection and the European incoherent scatter observations in the polar cap","authors":"R. Lukianova, A. Kozlovsky, T. Turunen","doi":"10.1029/2007GI000169","DOIUrl":"https://doi.org/10.1029/2007GI000169","url":null,"abstract":"[1] We use the ionospheric velocity measurements obtained by the European incoherent scatter (EISCAT) Svalbard radar (ESR) for comparison with the electric field distribution predicted by the new ionospheric convection model based on realistic maps of field-aligned currents. The comparative analysis of model output and observations is based on the data contained both the north–south and east–west components of the ionospheric electric field. Such a comparison provides an independent check of the model. It is shown that the model represents accurately the large-scale features of statistical electric field inferred from the ion velocity measured by the ESR. From observations and modeling we quantitatively determine the dependence of the ionospheric electric field strength on the IMF conditions and how this varies with magnetic local time. For specification of the relationship we derive average convection patterns for sorting by the magnitude and direction of the IMF. The dependence is clearly seen by contrasting the results for two magnitudes of the IMF strength (BT = 1 and 5 nT), for two opposite directions of the IMF Bz component, and for By+, By−. The magnitude of the IMF has the main impact on the average flows under southward IMF conditions. The sign of IMF By is the most important factor influenced the convection system under the IMF northward. For By− the northward component is negative during a major part of the day indicating counterclockwise plasma flow around the pole. For By+, the situation is opposite, the electric field is directed poleward and the plasma rotate clockwise. These are confirmed nicely by the ESR observations.","PeriodicalId":135868,"journal":{"name":"International Journal of Geomagnetism and Aeronomy","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126199890","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}

引用次数: 3

A method for restoration of radio channel transfer function by chirp sounding of the ionosphere 电离层啁啾测深恢复无线电信道传递函数的方法

International Journal of Geomagnetism and Aeronomy Pub Date : 2008-03-13 DOI: 10.1029/2006GI000158

M. A. Davydenko, N. V. Ilyin, V. Khakhinov

{"title":"A method for restoration of radio channel transfer function by chirp sounding of the ionosphere","authors":"M. A. Davydenko, N. V. Ilyin, V. Khakhinov","doi":"10.1029/2006GI000158","DOIUrl":"https://doi.org/10.1029/2006GI000158","url":null,"abstract":"[1] Analysis of both in-phase and quadrature components of received frequency-modulated continuous wave (FMCW) signal at the output of intermediate frequency (IF) band-pass filter of the chirp ionosonde demonstrates a new possibility of recovering the transfer function of the HF radio channel within the band of operating frequencies and the interval of time delays that are defined by the IF filter characteristics. The transfer function is determined by the parameters of all parts comprising the radio channel: transmitter, receiving-transmitting antenna-feeder devices, Earth surface, ionosphere, as well as the receiver circuitry participating in the signal processing. However, characteristics of all parts except the ionosphere can be considered stationary and well-known or controlled. It is the ionosphere that displays significant temporal variability. A new technique is proposed for recovering the transfer function of the ionospheric radio channel, together with its implementation as a signal preprocessing circuit containing a correcting digital filter that adapts to the current amplitude frequency and phase frequency characteristics of the channel. INDEX TERMS: 2441 Ionosphere: Ionospheric storms; 2407 Ionosphere: Auroral ionosphere; 2447 Ionosphere: Modeling and forecasting; KEYWORDS: FMCW sounder, chirp sounding technique, ionospheric radio channel, transfer function, digital signal processing.","PeriodicalId":135868,"journal":{"name":"International Journal of Geomagnetism and Aeronomy","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115708018","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}

引用次数: 2

Slow magnetosonic oscillations with m 1 in a dipole magnetosphere with rotating plasma 具有旋转等离子体的偶极磁层中具有m1的慢磁子振荡

International Journal of Geomagnetism and Aeronomy Pub Date : 2008-03-13 DOI: 10.1029/2006GI000164

D. Kozlov

引用次数: 3

Rate of proton intensity decay in solar cosmic ray events as a generalized characteristic of the interplanetary space 太阳宇宙射线事件中质子强度衰减率作为行星际空间的一般特征

International Journal of Geomagnetism and Aeronomy Pub Date : 2007-11-20 DOI: 10.1029/2006GI000154

E. Daibog, Y. Logachev, K. Kecskeméty

{"title":"Rate of proton intensity decay in solar cosmic ray events as a generalized characteristic of the interplanetary space","authors":"E. Daibog, Y. Logachev, K. Kecskeméty","doi":"10.1029/2006GI000154","DOIUrl":"https://doi.org/10.1029/2006GI000154","url":null,"abstract":"[1] The transport of solar energetic particles in interplanetary space is determined by the structure and dynamics of the solar wind between the source and the observer. The intensity time profile, in particular the decay phase, is determined by the transport processes. In this paper we discuss the decay phases of solar energetic proton events in the energy range 1‐48 MeV for the period 1974‐2001. For events with exponential shape of decay, the dependence of the characteristic time on the exponent of the energetic spectrum , the solar wind velocity V , and the proton energy E assumed in a form (E) = CE n is given. Such presentation allows us to consider the action of three main mechanisms of propagation (diusion, convection, and adiabatic cooling) that determine the value. It is shown that approximately half of decays with the constant value of V is described quite satisfactorily within the frame of the model with predominant convection and adiabatic deceleration in comparison with particle diusion. The dependence of n on heliolongitude of the parent flare (the source of particles) is investigated. INDEX TERMS: 2104 Interplanetary Physics: Cosmic rays; 2114 Interplanetary Physics: Energetic particles; 2194 Interplanetary Physics: Instruments and techniques;","PeriodicalId":135868,"journal":{"name":"International Journal of Geomagnetism and Aeronomy","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132649860","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}

引用次数: 2

Discussion paper: Comments on physical properties of strongest perturbations on the Sun in the heliosphere and the magnetosphere 讨论文件:关于太阳在日球层和磁层中最强扰动的物理性质的评论

International Journal of Geomagnetism and Aeronomy Pub Date : 2007-11-20 DOI: 10.1029/2005GI000133

O. S. Veselovsky, I. S. Yakovchouk

引用次数: 0

Dynamic processes in the ionosphere during magnetic storms from the Kharkov incoherent scatter radar observations 哈尔科夫非相干散射雷达观测磁暴期间电离层的动态过程

International Journal of Geomagnetism and Aeronomy Pub Date : 2007-10-26 DOI: 10.1029/2005GI000125

L. Chernogor, Y. Grigorenko, V. Lysenko, V. Taran

{"title":"Dynamic processes in the ionosphere during magnetic storms from the Kharkov incoherent scatter radar observations","authors":"L. Chernogor, Y. Grigorenko, V. Lysenko, V. Taran","doi":"10.1029/2005GI000125","DOIUrl":"https://doi.org/10.1029/2005GI000125","url":null,"abstract":"[1] Results of studying the ionosphere behavior during several magnetic storms of various intensities are presented. The features of pronounced negative ionospheric disturbances accompanying the severe magnetic storms on 25 September 1998 and 29‐30 May 2003 (Kp 8) are considered. Among them there are a decrease in the electron density by a factor of 3‐4, uplifting of the ionospheric F2 layer by 100‐160 km, increase in the temperature of the charged and neutral atmospheric components, and infringement of plasma transfer processes and thermal balance in the ionosphere‐plasmasphere system. In the morning of 25 September 1998, an unusual increase in the upward plasma drift velocity was registered. On 29‐30 May 2003 during the storm main phase, a depletion of the relative density of hydrogen ions by more than an order of magnitude was observed that could manifest an emptying of the magnetic flux tube over Kharkov. These eects are explained in terms of thermospheric disturbances, Joule heating, particle precipitation, penetration of magnetospheric electric fields to midlatitudes, the shift of the main ionospheric trough and related structures toward the radar latitude, etc. The ionospheric storm on 20‐21 March 2003 had two phases. Its strong negative phase proceeded against a background of a minor geomagnetic disturbance (Kp 5). The destabilizing impact of the electric field pulse and traveling atmospheric disturbance generated by magnetospheric substorms could be the cause of the change in the storm phase that occurred in the sunset period. INDEX TERMS: 2431 Ionosphere: Ionosphere/magnetosphere interactions; 2788 Magnetospheric Physics: Magnetic storms and substorms; 6969 Radio Science: Remote sensing; KEYWORDS: ionosphere; magnetic storms; incoherent scatter radar observations.","PeriodicalId":135868,"journal":{"name":"International Journal of Geomagnetism and Aeronomy","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124685454","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}

引用次数: 12

Application of the normal wave method to calculations of VLF electromagnetic fields in the anisotropic two-dimensionally inhomogeneous Earth-ionosphere waveguide 正波法在各向异性二维非均匀地球-电离层波导中VLF电磁场计算中的应用

International Journal of Geomagnetism and Aeronomy Pub Date : 2007-08-30 DOI: 10.1029/2005GI000127

L. N. Loutchenko, M. Bisyarin

引用次数: 0

Normal waves of the anisotropic Earth-ionosphere waveguide in the VLF-ULF range VLF-ULF范围内各向异性地球-电离层波导的正态波

International Journal of Geomagnetism and Aeronomy Pub Date : 2007-08-30 DOI: 10.1029/2005GI000126

V. Kirillov, A. E. Pronin

引用次数: 3