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Vlf/Elf Wave Activity in the Vicinity of the Polar Cusp: Cluster O...

By: H. Rème; N. Cornilleau-wehrlin; E. Lucek; M. Wilber; N. Lin; G. Parks; A. Fazakarley; J. McFadden; M. Maksimovic; E. S. Lee; O. Santolik; Q.-g. Zong

Description: Space Sciences Laboratory, UC Berkeley, Berkeley, CA 94720, USA. Observations by the Cluster spacecraft of VLF/ELF wave activity show distinct signatures for different regions in the vicinity of high altitude polar cusps, which are identified by using magnetic field and plasma data along spacecraft trajectories. These waves include: (1) Broad band magnetic noise observed in the polar cusp at frequencies from several Hz to ~100 Hz, below the local electr...

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Periodic Modulation of Gas Giant Magnetospheres by the Neutral Upp...

By: C. G. A. Smith

Description: Atmospheric Physics Laboratory, Department of Physics and Astronomy, University College, London, UK. Periodic signatures present in the magnetospheres of both Jupiter and Saturn have yet to be fully explained. At Jupiter the unexplained signatures are related to emissions from the Io torus (System IV); at Saturn they are observed in emissions of kilometric radiation (SKR) and in magnetometer data. These signatures are often interpreted in terms of magnet...

Banks, P. M. and Kockarts, G.: Aeronomy, Academic Press, 1973.; Brown, M. E.: Periodicities in the Io plasma torus, \jgr, 100, 21 683–21 696, 1995.; Bunce, E. J., Cowley, S. W. H., and Wild, J. A.: Azimuthal magnetic fields in Saturn's magnetosphere: effects associated with plasma subcorotation and the magnetopause-tail current system, \ag, 21, 1709–1722, 2003.; Cecconi, B. and Zarka, P.: Model of a variable radio period for Saturn, \jgr, 110, 12 203, doi:10.1029/2005JA0...

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The Polar Cliff in the Morning Sector of the Ionosphere : Volume 3...

By: G. W. Prölss

Description: Argelander Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany. By polar cliff we mean the steep increase in the ionization density observed in the morning sector of the polar ionosphere. Here the properties of this remarkable feature are investigated. The data set consists of electron density and temperature measurements obtained by the Dynamics Explorer 2 satellite. Only data recorded in the Northern Hemisphere winter are...

Andrews, M. and Thomas, J.: Electron density distribution above the winter pole, Nature, 221, 223–227, 1969.; Dudeney, J., Rodger, A., and Jarvis, M.: Radio studies of the main F region trough in Antarctica, Radio Sci., 18, 927–936, 1983.; Fang, X., Liemohn, M., Kozyra, J., and Evans, D.: Global 30–240 keV proton precipitation in the 17–18 April 2002 geomagnetic storms: 2. Conductances and beam spreading, J. Geophys. Res., 112, A05302,

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Method for Assessing the Amplitude Modulation of the Stationary Pl...

By: B. Andonov; D. Pancheva; P. Mukhtarov

Description: Geophysical Institute, Bulgarian Academy of Sciences, Sofia, Bulgaria. This short-communication presents a new method for assessing the amplitude modulation of the stationary planetary waves (SPWs). The suggested procedure allows estimating the contribution of the amplitude modulated SPWs to the field of the zonally travelling planetary waves. The root of the method consists in calculating of a quantity that is analogous to 2-D Lomb-Scargle amplitude sp...

Andrews, D. G., Holton, J. R., and Leovy, C. B.: Middle Atmosphere Dynamics, p. 489, Academic Press, San Diego, 1987.; Azeem, S. M., Talaat, E. R., Sivijee, G. G., Liu, H.-L., and Roble, R. G.: Observational study of the 4-day wave in the mesosphere preceding the sudden stratospheric warming events during 1995 and 2002, Geophys. Res. Lett., 32, L15804, doi:10.1029/2005GL023393, 2005.; Charney, J. G. and Drazin, P. G.: Propagation of planetary-scale disturbances from the ...

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Eddy Turbulence Parameters Inferred from Radar Observations at Jic...

By: D. L. Hysell; M. C. Kelley; M. N. Vlasov

Description: School of Electrical and Computer Engineering, Cornell University, 320 Rhodes Hall, Ithaca, New York, 14853, USA. Significant electron density striations, neutral temperatures 27 K above nominal, and intense wind shear were observed in the E-region ionosphere over the Jicamarca Radio Observatory during an unusual event on 26 July 2005 (Hysell et al., 2007). In this paper, these results are used to estimate eddy turbulence parameters and their effects. Mo...

Hocking, W.: Turbulence in the region 80-120 km, Adv. Space Res., 7, 171–181, 1987.; Hysell, D. L. and Chau, J. L.: Imaging radar observations and nonlocal theory of large-scale waves in the equatorial electrojet, Ann. Geophys., 20, 1167–1179, 2002.; Hysell, D. L. and Chau, J. L.: Optimal aperture synthesis radar imaging, Radio Sci., 41, RS2003, doi:10.1029/2005RS003383, 2006.; Banks, P. M. and Kockarts, G.: Aeronomy, Part A, Academic Press, San Diego, Calif., 1973.; Bil...

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Solar Wind Modulation of the Martian Ionosphere Observed by Mars G...

By: E. Nielsen; J.-s. Wang

Description: Max-Planck-Institut für Aeronomie, 37191 Katlenburg-Lindau, Germany. Electron density profiles in the Martian ionosphere observed by the radio occultation experiment on board Mars Global Surveyor have been analyzed to determine if the densities are influenced by the solar wind. Evidence is presented that the altitude of the maximum ionospheric electron density shows a positive correlation to the energetic proton flux in the solar wind. The solar wind mo...

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Estimating the Magnetic Energy Inside Traveling Compression Region...

By: V. V. Ivanova; W. Baumjohann; H. K. Biernat; V. S. Semenov; S. A. Kiehas; R. Nakamura

Description: Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, 8042 Graz, Austria. We investigate a series of six TCRs (traveling compression regions), appearing in the course of a small substorm on 19 September 2001. Except for two of these TCRs, all Cluster spacecraft were located in the lobe and detected the typical signatures of TCRs, i.e., compressions in |B| and bipolar Bz variations. We use these perturbations in...

Baker, D. N., Pulkkinen, T. I., Angelopoulos, V., Baumjohann, W., and McPherron, R. L.: Neutral line model of substorms: Past results and present view, J. Geophys. Res., 101, 12975–13010, 1996. \bibitem[] Biernat, H K.,~Heyn, M F., and~Semenov, V S.: Unsteady Petschek reconnection, J. Geophys. Res., 92, 3392–3396, 1987.; Borälv, E., Opgenoorth, H. J., Kauristie, K., Lester, M., Bosqued, J.-M., Dewhurst, J. P., Owen, C. J., Dunlop, M., Slavin, J. A., Fazakerley, A., and P...

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Multi-scale Analysis of Turbulence in the Earth's Current Sheet : ...

By: T. L. Zhang; W. Baumjohann; R. Nakamura; M. Volwerk; H. Rème; A. Runov; K.-h. Glassmeier; B. Klecker; A. Balogh; R. A. Treumann; Z. Vörös

Description: IWF, ÖAW, Graz, Austria. A multi-scale analysis of magnetotail turbulence in the Earth's tail current sheet is presented based on Cluster magnetometer observations. Both Fourier and wavelet analysis is used to describe the spectral index and scaling indices of the turbulence for different frequency regions. Flows in the tail are very important for driving the observed turbulence. There is a strong correlation between the maximum perpendicular flow veloc...

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Electron-cylotron Maser Radiation from Electron Holes: Downward Cu...

By: W. Baumjohann; R. Pottelette; R. A. Treumann

Description: Department of Geophysics and Environmental Sciences, Munich University, Munich, Germany. The electron-cyclotron maser emission theory from electron holes is applied to holes generated in the downward current region of the aurora. It is argued that the main background auroral kilometric radiation source may still be located in the upward current region electron-ring (horseshoe) distribution while the fine structure is caused by electron holes predominant...

Andersson, L., Ergun, R. E., Newman, D. L., McFadden, J. P., and Carlson, C. W.: Characteristics of parallel electric fields in the downward current region of the aurora, Phys. Plasmas, 9, 3600, doi:10.1063/1.1490134, 2002.; Baumjohann, W. and Treumann, R. A.: Basic Space Plasma Physics, Imperial College Press, London, pp. 228–234, 1996.; Berman, R. H., Dupree, T. H., and Tetreault, D. J.: Growth of nonlinear intermittent f...

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Density and Temperature of Energetic Electrons in the Earth's Magn...

By: M. H. Denton; T. E. Cayton

Description: Department of Physics, Lancaster University, Lancaster, LA1 4YB, UK. Single relativistic-Maxwellian fits are made to high-latitude GPS-satellite observations of energetic electrons for the period January 2006–November 2010; a constellation of 12 GPS space vehicles provides the observations. The derived fit parameters (for energies ~0.1–1.0 MeV), in combination with field-line mapping on the nightside of the magnetosphere, provide a survey of the energet...

Montgomery, M. D.: Observations in the Earth's magnetotail by Vela Launch 2 Satellites, J. Geophys. Res., 73, 871–889, 1968.; Åsnes, A., Friedel, R. W. H., Lavraud, B., Reeves, G. D., Taylor, M. G. G. T., and Daly, P.: Statistical properties of tail plasma sheet electrons above 40 keV, J. Geophys. Res., 113, A03202, doi:10.1029/2007JA012502, 2008.; Baker, D. N. and Stone, E. C.: Energetic electron anisotropies in the mag...

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Cluster Observation of Plasma Flow Reversal in the Magnetotail Dur...

By: M. W. Dunlop; Y. Zhang; S. Livi; G. Gustafsson; C. Mouikis; L. M. Kistler; H. Rème; A. T. Y. Lui; S. B. Mende; Y. Zheng

Description: JHU/APL, Laurel, MD 20723-6099, USA. We investigate in detail a reversal of plasma flow from tailward to earthward detected by Cluster at the downstream distance of ~19 RE in the midnight sector of the magnetotail on 22 August 2001. This flow reversal was accompanied by a sign reversal of the Bz component and occurred during the late substorm expansion phase as revealed by simultaneous global view of auroral activity ...

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Zonal Velocity of the Equatorial Plasma Bubbles Over Kolhapur, Ind...

By: S. S. Nikte; P. T. Patil; A. K. Sharma; M. V. Rokade; S. Gurubaran; D. P. Nade; R. N. Ghodpage; Y. Sahai; A. Taori

Description: Earth and Space Science Laboratory, Department of Physics, Shivaji University, Kolhapur, India. This paper presents the observations of zonal drift velocities of equatorial ionospheric plasma bubbles and their comparison with model values. These velocities are determined by nightglow OI 630.0 nm images. The nightglow observations have been carried out from the low latitude station Kolhapur (16.8° N, 74.2° E; 10.6° N dip lat.) during clear moonless night...

Bates, D. R.: Emission of forbidden red and green lines of atomic oxygen from the nocturnal F region, Plonel. Sprrce Sci., 40, 893–899, 1992.; Bitten-court, J. A. and Sahai, Y.: F region neutral winds from ionosonde measurements of hmf2 at low-latitude magnetic conjugate regions, J. Atmos. Terr. Phys., 40, 669–676, 1978.; Clemesha, B. R. and Takahashi, H.: Airglow studies via rocket–borne photometers in Brazil, Braz. J. Geophys., 11, 139–155, 1993.; DasGupta, A., ...

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The Nonlinear Effects on the Characteristics of Gravity Wave Packe...

By: J.-f. Wang; S.-d. Zhang; F. Yi

Description: Department of Space Physics, Wuhan University, Wuhan, 430072, P. R. China. By analyzing the results of the numerical simulations of nonlinear propagation of three Gaussian gravity-wave packets in isothermal atmosphere individually, the nonlinear effects on the characteristics of gravity waves are studied quantitatively. The analyses show that during the nonlinear propagation of gravity wave packets the mean flows are accelerated and the vertical wavelen...

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Observation of Two Distinct Cold, Dense Ion Populations at Geosync...

By: S. Wing; J. E. Borovsky; M. Fujimoto; M. F. Thomsen; A. Aasnes; M. H. Denton; J. M. Weygand; B. Lavraud; K. Seki

Description: Space Science and Applications, Los Alamos National Laboratory, Los Alamos, New Mexico, USA. We report on the observation of two distinct cold (Ti<5 keV), dense (Ni>2 cm−3) ion populations at geosynchronous orbit. A statistical study was performed on measurements from the geosynchronous Los Alamos plasma instruments, for the period 1990–2004, and complemented by corresponding large-scale plasma sheet data ob...

Bame, S. J., McComas, D. J., Thomsen, M. F., Barraclough, B. L., Elphic, R. C., Glore, J. P., Gosling, J. T., Chavez, J. C., Evans, E. P., and Wymer, J. F.: Magnetospheric plasma analyzer for spacecraft with restrained resources, Rev. Sci. Instrum., 64, No. 4, 1026–1033, 1993.; Bernstein, W., Hultqvist, B., and Borg, H.: Some implications of low altitude observations of isotropic precipitation of ring current protons beyond the plasmapause, Planet. Space Sci., 22, 767–77...

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Magion 5 Observations of Chorus-like Emissions and Their Propagati...

By: D. Shklyar; J. Šmilauer; F. Jiříček; J. Chum

Description: Institute of Atmospheric Physics, Bocni II/1401, 14131 Praha 4, Czech Republic. After reviewing briefly the present state of knowledge about chorus-like emissions, we present an overview of Magion 5 satellite observations of these emissions in the inner magnetosphere of the Earth. From the extensive VLF data recorded on board the Magion 5 satellite, we show examples of different types of discrete elements, representing rising and falling tones, and...

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