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New Insights Into the Stratospheric and Mesosphere-lower Thermosph...

By: Subrahmanyam; Sherine Rachel John; K. V. Karanam Kishore Kumar

Description: Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram-695022, India. Using a unique set of satellite based observations of the vertical distribution of ozone during the recent annular solar eclipse of 15 January 2010, we demonstrate for the first time, a complete picture of the response of stratospheric ozone to abrupt changes in solar forcing. The stratospheric ozone decreased after the maximum obscuration of the Sun and then gradu...

Bojkov, R. D.: The ozone variations during the solar eclipse of 20 May 1966, Tellus 20, 417–421, 1968.; Chakrabarty, D. K., Shah, N. C., and Pandya, K. V.: Fluctuation in ozone column over Ahmedabad, during the solar eclipse of 24 October 1995, Geophys. Res. Lett., 24, 3001–3003, 1997.; Chakrabarty, D. K., Peshin, S. K., Pandya, K. V., and Shah, N. C.: Long-term trend of ozone column over the Indian region, J. Geophys. Res., 103, 19245–19251, 1998.; Chandra, S., Ziemke, ...

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First Mesospheric Turbulence Study Using Coordinated Rocket and Ms...

By: U. Das; J. Datta; H. S. S. Sinha; S. C. Chakravarty; S. R. Das; H. Chandra; A. K. Patra; D. Narayana Rao; R. N. Misra; N. Venkateswara Rao

Description: Physical Research Laboratory, Ahmedabad, India. A campaign to study turbulence in the mesosphere, over low latitudes in India, using rocket-borne measurements and Indian MST radar, was conducted during July 2004. A rocket-borne Langmuir probe detected a spectrum of electron density irregularities, with scale sizes in the range of about 1 m to 1 km, in 67.5–78.0 km and 84–89 km altitude regions over a low latitude station Sriharikota (13.6° N, 80.2° E). ...

Balsley, B. B. and Gage, K. S.: The MST Radar Technique: Potential for Middle Atmospheric Studies, Pageoph, 18, 453–493, 1980.; Blood, S. P., Mitchell. J. D., Croskey. C. L., Raymund, T. D., Thrane, E. V., Blix, T. A., Hopp, U. V., Fritts, D. C., and Schmidlin, F. J.: Studies of high latitude mesospheric turbulence by radar and rocket 2: measurements of small scale turbulence, J. Atmos. Terr. Phys., 50, 963–976, 1988.; Chakrabarty, D. K., Beig, G., Sidhu, J. S., and Das,...

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Enhanced Ion Acoustic Lines Due to Strong Ion Cyclotron Wave Field...

By: R. Cosgrove; H. Bahcivan

Description: Center for Geospace Studies, SRI International, Menlo Park, CA, USA. The Fast Auroral Snapshot Explorer (FAST) satellite detected intense and coherent 5–20 m electric field structures in the high-latitude topside auroral ionosphere between the altitudes of 350 km and 650 km. These electric fields appear to belong to electrostatic ion cyclotron (EIC) waves in terms of their frequency and wavelengths. Numerical simulations of the response of an electron ...

Ott, E. and Farley, D T.: Microinstabilities and production of short wavelength irregularities in the auroral F region, J. Geophys. Res., 80(34), 4599–4602, 1975.; Agrimson, E., D'Angelo, N., and Merlino, R.: Excitation of ion-acoustic-like waves by subcritical currents in a plasma having equal electron and ion temperatures, Phys. Rev. Lett., 86(23), 5282–5285, 2001.; Bering, E A.: The plasma wave environment of an auroral arc: electrostatic ion cyclotron waves in the di...

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Stereoscopic Determination of All-sky Altitude Map of Aurora Using...

By: T. Kubo; T. Nakai; T. Takahei; A. Yamashita; D. Hampton; Y. Mori; Y. Miyoshi; R. Kataoka; K. Shigematsu; M. Tanaka; H. Miyahara; K. Shiokawa

Description: National Institute of Polar Research, 10-3, Midoricho, Tachikawa, Tokyo 190-8518, Japan. A new stereoscopic measurement technique is developed to obtain an all-sky altitude map of aurora using two ground-based digital single-lens reflex (DSLR) cameras. Two identical full-color all-sky cameras were set with an 8 km separation across the Chatanika area in Alaska (Poker Flat Research Range and Aurora Borealis Lodge) to find localized emission height with th...

Aso, T., Hashimoto, T., Abe, M., Ono, T., and Ejiri, M.: On the analysis of aurora stereo observations, J. Geomag. Geoelectr., 42, 579–595, 1990.; Aso, T., Ejiri, M., Urashima, A., Miyaoka, H., Steen, Å., Brändström, U., and Gustavsson, B.: First results of auroral tomography from ALIS-Japan multi-station observations in March, 1995, Earth Planets Space, 50, 81–86, 1998.; Brown, N. B., Davis, T. N., Hallinan, T. J., Stenbaek-Nielsen, H. C.: Altitude of pulsating aurora d...

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The Combined Effects of Electrojet Strength and the Geomagnetic Ac...

By: R. Sridharan; D. S. V. V. D. Prasad; P. V. S. Rama Rao; S. Tulasi Ram; C. V. Devasia; Sudha Ravindran; A. Raja Babu; K. Niranjan

Description: Space Physics Laboratories, Department of Physics, Andhra University, Visakhapatnam, India. Several investigations have been carried out to identify the factors that are responsible for the day-to-day variability in the occurrence of equatorial spread-F (ESF). But the precise forecasting of ESF on a day-to-day basis is still far from reality. The nonlinear development and the sustenance of ESF/plasma bubbles is decided by the background ionospheric cond...

Anderson, D. N., Reinisch, B., Valladares, C., Chau, J., and Veliz, O.: Forecasting the occurrence of ionospheric scintillation activity in the equatorial ionosphere on a day-to-day basis, J. Atmos. Terr. Phys., 66, 1567–1572, 2004.; Basu, S., Kudeki, E., Bsau, Su., et al.: Scintillations, Plasma drifts,and neutral winds in the equatorial ionosphere after sunset, J.Geophys. Res., 101, 26 795–26 809, 1996.; Haerendel, G.: Theroy of equatorial spread F, report, Max-Planck ...

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The Pressure Tensor in Tangential Equilibria : Volume 22, Issue 8 ...

By: F. Mottez

Description: Centre d’études des Environnements Terrestre et Planétaires, CETP/IPSL/CNRS, Vélizy, France. The tangential equilibria are characterized by a bulk plasma velocity and a magnetic field that are perpendicular to the gradient direction. Such equilibria can be spatially periodic (like waves), or they can separate two regions with asymptotic uniform conditions (like MHD tangential discontinuities). It is possible to compute the velocity moments of the partic...

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A Straightforward Estimation of the Maximum Sunspot Number for Cyc...

By: B. Mendoza; J. Ramírez

Description: Insituto de Geofisica UNAM, Ciudad Universitaria, 04510 México D.F., MEXICO. Using the annual number of geomagnetically quiet days (aa < 20 γ) for the year after the solar minimum, this precursor method predicts that the maximum sunspot number for cycle 23 will be 140 ± 32, indicating that cycle 23 will be similar to cycles 21 and 22.

Key words. Solar physics · astrophysics and astronomy (magnetic fields; general)

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Geomagnetic and Ionospheric Data Analysis Over Antarctica: a Contr...

By: G. De Franceschi; A. De Santis; L. Alfonsi

Description: Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata, 605, 00143 Rome, Italy. The analysis of the foF2 ionosonde data acquired at mid and high latitudes reveals a general decreasing of the F2 plasma frequency over more than two solar cycles, showing steeper trends over the high latitude stations and, in particular, over Antarctica. A careful analysis of the foF2 hourly data, opportunely catalogued in different levels of magne...

Alfonsi, L., De Franceschi, G., and Perrone, L.: Long-term trend in the high latitude ionosphere, Physics and Chemistry of the Earth 26/5, 303-307, 2001.; Alfonsi, L., De Franceschi, G., Perrone, L., Materassi, M.: Long term trends of the critical frequency of the f2 layer at northern and southern high latitude regions, Phys. Chem. Earth, 27/6-8, 595–600, 2002.; Bremer, J.: Ionospheric trends in mid-latitudes as a possible indicator of the atmospheric greenhouse effect, ...

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Equatorial Scintillations in Relation to the Development of Ioniza...

By: A. Paul; A. Dasgupta; S. Ray

Description: S. K. Mitra Center for Research in Space Enviornment, University of Calcutta, Calcutta, India. The irregularities in the electron density distribution of the ionosphere over the equatorial region frequently disrupt space-based communication and navigation links by causing severe amplitude and phase scintillations of signals. Development of a specification and forecast system for scintillations is needed in view of the increased reliance on space-based c...

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An Interpretation of the ƑoF2 and HmF2 Long-term Trends in the Fra...

By: D. Marin; A. V. Mikhailov

Description: Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Troitsk, Moscow Region 142190, Russia. Earlier revealed morphological features of the foF2 and hmF2 long-term trends are interpreted in the scope of the geomagnetic control concept based on the contemporary F2-layer storm mechanisms. The F2-layer parameter trends strongly depend on the long-term varying geomagnetic activity whose effects cannot be removed from ...

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The Twins Exospheric Neutral H-density Distribution Under Solar Mi...

By: J. H. Zoennchen; H. J. Fahr; U. Nass; M. Gruntman; J. Goldstein; J. J. Bailey

Description: Argelander Institut für Astronomie, Astrophysics Department, University of Bonn, Auf dem Huegel 71, 53121 Bonn, Germany. Terrestrial exospheric atomic hydrogen (H) resonantly scatters solar Lyman-α (121.567 nm) radiation, observed as the glow of the H-geocorona. The Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) satellites are equiped with two Lyman-α line-of-sight Detectors (LADs) each. Since during the past solar minimum conditions the relev...

Fahr, H. J. and Shizgal, B.: Modern Exospheric Theories and Their Observational Relevance, Rev. Geophys. Space Phys., 21, 75–124, 1983.; Bailey, J. and Gruntman, M.: Experimental study of exospheric hydrogen atom distributions by \Lymana detectors on the TWINS mission, J. Geophys. Res., 116, A09302, doi:10.1029/2011JA016531, 2011.; Bertaux, J. L., Quémerais, E., Lallement, R., Kyrölä, E., Schmidt, W., Summanen, T., Gouta...

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Letter to the Editor: Electric Field Fluctuations (25-35 Min) in t...

By: T. -i. Kitamura; H. Tachihara; J. Hanumath Sastri; J. V. S. V. Rao; H. Luhr

Description: Indian Institute of Astrophysics, Bangalore 560 034, India. Measurements with a HF Doppler sounder at Kodaikanal (10.2°N, 77.5°E, geomagnetic latitude 0.8°N) showed conspicuous quasi-periodic fluctuations (period 25-35 min) in F region vertical plasma drift, Vz in the interval 0047-0210 IST on the night of 23/24 December, 1991 (Ap = 14, Kp < 4-). The fluctuations in F region vertical drift...

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Comparison of Ecmwf Analyses with Gps Radio Occultations from Cham...

By: G. Schwarz; S. Heise; J. Wickert; T. Schmidt; L. Zenner; E. Fagiolini; F. Flechtner; T. Gruber

Description: Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg A17, 14473 Potsdam, Germany. A climatological validation of the 6-hourly operational ECMWF troposphere and lower stratosphere temperatures as well as geopotential heights between 1000 and 10 hPa is performed using the 2001–2007 (80 months from May 2001 to December 2007) CHAMP radio occultation data. Generally there is a good agreement between ECMWF and CHAMP temperature...

Anthes, R. A., Bernhardt, P. A., Chen, Y., et al.: The COSMIC/FORMOSAT-3 mission: Early results, B. Am. Meteorol. Soc., 89, 1–21, 2008.; Bormann, N. and Healy, S. B.: New observations in the ECMWF assimilation system: Satellite limb measurements, ECMWF Newsletter, 105, 13–17, 2005.; Borsche, M., Kirchengast, G., and Foelsche, U.: Tropical tropopause climatology as observed with radio occultation measurements from CHAMP compared to ECMWF and NCEP analyses, Geophys. Res. L...

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Origin of Temperature Anisotropies in the Cold Plasma Sheet: Geota...

By: G. Ueno; M. Fujimoto; T. Mukai; Y. Saito; M. N. Nishino

Description: School of Science, The University of Tokyo, Tokyo 113-0033, Japan. To further our understanding of the solar wind entry across the magnetopause under northward IMF, we perform a case study of a duskside Kelvin-Helmholtz (KH) vortex event on 24 March 1995. We have found that the protons consist of two separate (cold and hot) components in the magnetosphere-like region inside the KH vortical structure. The cold proton component occasionally consisted of c...

Borovsky, J. E., Thomsen, M. F., and Elphic, R. C.: The driving of the plasma sheet by the solar wind, J. Geophys. Res., 103(A8), 17 617–17 639, 1998.; Cattell, C., Crumley, J., Dombeck, J., and Wygant, J.: Polar observations of solitary waves at the Earth's magnetopause, Geophys. Res. Lett., 29, 1065, doi:10.1029/2001GL014046, 2002.; Davidson, R. C., Krall, N. A., Papadopoulos, K., and Shanny, R.: Electron heating by electron-ion beam instabilities, Phys. Rev. Lett., 24...

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Plasma Parameter Analysis of the Langmuir Decay Process Via Partic...

By: M. Oppenheim; M. Zettergren; J. L. Semeter; M. A. Diaz

Description: Electrical Engineering Department, University of Chile, Santiago, Chile. The beam-plasma mechanism, based on the Langmuir decay process, has been proposed to explain naturally enhanced ion-acoustic lines (NEIALs), which are spectral distortions in incoherent scatter radar (ISR) data frequently observed in the vicinity of auroral arcs. In this work the effect of the Langmuir decay process on the ISR spectrum is studied and compared with an analytical mod...

Boyd, T. and Sanderson, J.: The physics of plasmas, Cambridge Univ Pr., 2003.; Akbari, H., Semeter, J., Dahlgren, H., Diaz, M., Zettergren, M., Strømme, A., Nicolls, M., and Heinselman, C.: Anomalous ISR echoes preceding auroral breakup: Evidence for strong Langmuir turbulence, Geophys. Res. Lett., 39, L03102, doi:10.1029/2011GL050288, 2012.; Bahcivan, H. and Cosgrove, R.: Enhanced ion acoustic lines due to strong ion cy...

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Gravity Wave Propagation Through a Large Semidiurnal Tide and Inst...

By: C. Y. She; D. C. Fritts; R. A. Goldberg; B. P. Williams

Description: Northwest Research Associates, Colorado Research Associates division, Boulder, Colorado, USA. The winter MaCWAVE (Mountain and convective waves ascending vertically) rocket campaign took place in January 2003 at Esrange, Sweden and the ALOMAR observatory in Andenes, Norway. The campaign combined balloon, lidar, radar, and rocket measurements to produce full temperature and wind profiles from the ground to 105 km. This paper will investigate gravity wave ...

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Magnetic Clouds Seen at Different Locations in the Heliosphere : V...

By: C. Cid; C. H. Mandrini; S. Dasso; B. Schmieder; S. Poedts; A. N. Zhukov; H. Cremades; Y. Cerrato; A. Aran; L. Rodriguez; E. Saiz; M. Menvielle

Description: Solar Influences Data analysis Center, Royal Observatory of Belgium, Brussels, Belgium. We analyze two magnetic clouds (MCs) observed in different points of the heliosphere. The main aim of the present study is to provide a link between the different aspects of this phenomenon, starting with information on the origins of the MCs at the Sun and following by the analysis of in-situ observations at 1 AU and at Ulysses. The candidate source regions were ide...

Berger, M. A.: Rigorous new limits on magnetic helicity dissipation in the solar corona, Geophys. Astrophys. Fluid Dynam., 30, 79–104, 1984.; Bothmer, V. and Schwenn, R.: The structure and origin of magnetic clouds in the solar wind, Ann. Geophys., 16, 1–24, 1998.; Brueckner, G. E., Howard, R. A., Koomen, M. J., Korendyke, C. M., Michels, D. J., Moses, J. D., Socker, D. G., Dere, K. P., Lamy, P. L., Llebaria, A., Bout, M. V., Schwenn, R., Simnett, G. M., Bedford, D. K., ...

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Temporal Evolution of Two Auroral Arcs as Measured by the Cluster ...

By: K. Mursula; G. Marklund; S. Buchert; O. Amm; M. Dunlop; A. T. Aikio; A. Vaivads; A. Fazakerley; D. Fontaine; F. Forme

Description: University of Oulu, Department of Physical Sciences, P.O. Box 3000, FIN-90014 University of Oulu, Finland. The four Cluster s/c passed over Northern Scandinavia on 6 February 2001 from south-east to north-west at a radial distance of about 4.4 RE in the post-midnight sector. When mapped along geomagnetic field lines, the separation of the spacecraft in the ionosphere was confined to within 110km in latitude and 50km in longitude. This ...

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Magnetohydrodynamic Modeling of Three Van Allen Probes Storms in 2...

By: M. K. Hudson; B. T. Kress; H. J. Singer; J. R. Wygant; J. Paral; M. J. Wiltberger

Description: Department of Physics and Astronomy, Dartmouth College, Hanover, NH, USA. Coronal mass ejection (CME)-shock compression of the dayside magnetopause has been observed to cause both prompt enhancement of radiation belt electron flux due to inward radial transport of electrons conserving their first adiabatic invariant and prompt losses which at times entirely eliminate the outer zone. Recent numerical studies suggest that enhanced ultra-low frequency (...

Anderson, B. J., Erlandson, R. E., and Zanetti, L. J.: A Statistical Study of Pc 1-2 Magnetic Pulsations in the Equatorial Magnetosphere, 1. Equatorial Occurrence Distributions, J. Geophys. Res., 97, 3075–3088, doi:10.1029/91JA02706, 1992a.; Anderson, B. J., Erlandson, R. E., and Zanetti, L. J.: A Statistical Study of Pc 1-2 Magnetic Pulsations in the Equatorial Magnetosphere, 2. Wave Properties, J. Geophys. Res., 97, 3089–...

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