8 results on '"Villedary J"'
Search Results
2. [MacLeod's syndrome (pulmonary hypertransparence and unilateral vascular hypoplasia in a young infant)].
- Author
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Martin PL, Bricaud H, Besse P, Broustet JP, Sagardiluz J, Choussat A, Villedary J, and Broustet P
- Subjects
- Age Factors, Auscultation, Humans, Infant, Male, Radiography, Lung diagnostic imaging, Pulmonary Emphysema diagnostic imaging
- Published
- 1969
3. Auroral Processes at the Giant Planets: Energy Deposition, Emission Mechanisms, Morphology and Spectra.
- Author
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Badman, Sarah V., Branduardi-Raymont, Graziella, Galand, Marina, Hess, Sébastien L. G., Krupp, Norbert, Lamy, Laurent, Melin, Henrik, and Tao, Chihiro
- Published
- 2016
- Full Text
- View/download PDF
4. Quasielectrostatic instabilities excited by energetic oxygen ions in the ring current region.
- Author
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Singh, S. V., Kakad, A. P., and Lakhina, G. S.
- Subjects
IONS ,PARTICLES (Nuclear physics) ,CATHODE rays ,CHARGE transfer ,COLLISIONS (Nuclear physics) ,ATOMS - Abstract
Quasielectrostatic instabilities driven by anisotropic oxygen ions are investigated during storms/substorms in three-component ring current plasma consisting of electrons, protons, and energetic oxygen ions having loss-cone distribution. The response of the electrons is fully electromagnetic and that of the protons and oxygen ions is electrostatic. The electrons, protons, and oxygen ions are treated as magnetized. Obliquely propagating modes with frequencies near the harmonics of the oxygen ion cyclotron frequency are found to become unstable due to pressure anisotropy of the energetic oxygen ions. The results are applied to storm-time ring-current region parameters. The loss of energetic particles resulting from wave-particle interaction may provide an alternate mechanism, complimentary to and independent of the charge exchange process for the ring-current decay. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
5. Investigation of an ion-ion hybrid Alfvén wave resonator.
- Author
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Vincena, S. T., Farmer, W. A., Maggs, J. E., and Morales, G. J.
- Subjects
ION-ion collisions ,HYBRID systems ,MAGNETOHYDRODYNAMIC waves ,PHYSICS experiments ,MAGNETIC fields ,MAGNETIZATION ,PLASMA gases ,PREDICTION models - Abstract
A theoretical and experimental investigation is made of a wave resonator based on the concept of wave reflection along the confinement magnetic field at a spatial location where the wave frequency matches the local value of the ion-ion hybrid frequency. Such a situation can be realized by shear Alfvén waves in a magnetized plasma with two ion species because this mode has zero parallel group velocity and experiences a cut-off at the ion-ion hybrid frequency. Since the ion-ion hybrid frequency is proportional to the magnetic field, it is expected that a magnetic well configuration in a two-ion plasma can result in an Alfvén wave resonator. Such a concept has been proposed in various space plasma studies and could have relevance to mirror and tokamak fusion devices. This study demonstrates such a resonator in a controlled laboratory experiment using a H+-He+ mixture. The resonator response is investigated by launching monochromatic waves and impulses from a magnetic loop antenna. The observed frequency spectra are found to agree with predictions of a theoretical model of trapped eigenmodes. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
6. Geomagnetosphere and Coupling Phenomena
- Author
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Dorman, L. I. and Dorman, L. I.
- Subjects
- Cosmic rays, Magnetic storms, Solar wind, Magnetosphere, Geomagnetism, Ionosphere
- Abstract
The present review book by Prof., Dr. Lev I. Dorman, Plasmas and Energetic Processes in Geomagnetosphere reflects the development of the geomagnetosphere's research and applications for the last few decades. The importance and actuality of geomagnetosphere research are based on the following three factors: 1. The geomagnetosphere is the nearest giant natural laboratory, where it is possible via satellites and ground measurements to investigate in detail many different plasmas and energetic processes in space, which are caused by an interaction of high kinetic energy solar wind plasmas and its perturbations (Interplanetary Coronal Mass Ejections - ICMEs, Interplanetary Shock Waves – ISWs, Interplanetary Interaction Regions – IIR), including those frozen in the Interplanetary Magnetic Fields (IMF) with the rotated main geomagnetic field. This interaction leads to the dynamic transformation of magnetic fields in the geomagnetosphere, generation and trapping of high energy particles (which are known as Magnetospheric Cosmic Rays – MCR), and the generation of many types of instabilities and electromagnetic radiations. These processes are in principle similar to processes in magnetospheres of other planets and their moons, in the atmosphere of the sun and other stars, in interplanetary and in interstellar space, and in many different astrophysical objects. This research is an important basis for fundamental space and astrophysical science. 2. Today, technology, economics, navigation, TV, Internet, radio connections, military aspects, and the life of people on our planet are strongly connected to the work of many satellites moving inside the geomagnetosphere. Different processes and MCR in the geomagnetosphere influence the satellites'work and often lead to satellite malfunctions up to fully destroying their electronics; satellites essentially “die” in these cases. The described research can be considered as a basis for developing methods of forecasting dangerous situations for satellites in different orbits and to decrease the risk of satellite malfunctions and loss. 3. The interaction of ICME, ISW, and IIR with the geomagnetosphere leads to the generation of big magnetic storms accompanied with a Forbush decrease and precursory effects in Galactic Cosmic Ray (GCR) intensity. These magnetic storms are dangerous not only to satellites, but also to the Earth's surface in terms of technology, radio connections, car accidents, and human health (e.g., increasing the frequency of infarct myocardial and brain strokes). Investigations of causes of magnetic storms can help to develop methods of forecasting and decreasing the level of magnetic storm hazards. Therefore, the other practical application of this research is connected with the problem of space weather and space climate influence on the technology, radio connections, navigation, transportation, and people's health on the Earth, which is independent of altitude and geomagnetic latitude. Volume I of the book, Geomagnetosphere and Coupling Phenomena, includes the following chapters: Chapter 1. Coupling and Energy Transfer: Time Variations and Main Problems Chapter 2. Coupling of Solar Wind/IMF with Geomagnetosphere/Ionosphere Chapter 3. Efficiency of Solar Wind-Magnetosphere Coupling for SW Pressure Variations Chapter 4. Coupling of Space Factors with High Latitude Magnetospheric Activity Chapter 5. Coupling of Interplanetary ShW, CME and CIR with Magnetospheric Activity Chapter 6. Geomagnetosphere-Ionosphere System Coupling with Processes in Space and in the Atmosphere The author hopes that this book will be interesting and useful for researches, engineers, students, and all people interested in developing modern technologies in space and in problems concerning the geomagnetosphere, ionosphere, upper and lower atmosphere, cosmic rays, space weather and space climate influence on the Earth.
- Published
- 2017
7. The Magnetodiscs and Aurorae of Giant Planets
- Author
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Karoly Szego, Nicholas Achilleos, Chris Arridge, Sarah Badman, Peter Delamere, Denis Grodent, Margaret Galland Kivelson, Philippe Louarn, Karoly Szego, Nicholas Achilleos, Chris Arridge, Sarah Badman, Peter Delamere, Denis Grodent, Margaret Galland Kivelson, and Philippe Louarn
- Subjects
- Auroras, Planets--Magnetospheres
- Abstract
Readers will find grouped together here the most recent observations, current theoretical models and present understanding of the coupled atmosphere, magnetosphere and solar wind system. The book begins with a general discussion of mass, energy and momentum transport in magnetodiscs. The physics of partially ionized plasmas of the giant planet magnetodiscs is of general interest throughout the field of space physics, heliophysics and astrophysical plasmas; therefore, understanding the basic physical processes associated with magnetodiscs has universal applications. The second chapter characterizes the solar wind interaction and auroral responses to solar wind driven dynamics. The third chapter describes the role of magnetic reconnection and the effects on plasma transport. Finally, the last chapter characterizes the spectral and spatial properties of auroral emissions, distinguishing between solar wind drivers and internal driving mechanisms. The in-depth reviews provide an excellent reference for future research in this discipline.
- Published
- 2015
8. Ulysses radio and plasma wave observations in the Jupiter environment
- Author
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Stone, R.G., Pedersen, B.M., Harvey, C.C., Canu, P., Cornilleau-Wehrlin, N., Desch, M.D., Villedary, C. de, Fainberg, J., Farrell, W.M., Goetz, K., Hess, R.A., Hoang, S., Kaiser, M.L., Kellogg, P.J., Lecacheaux, A., Lin, N., MacDowall, R.J., Manning, R., Meetre, C.A., Meyer-Vernet, N., Moncuquet, M., Osherovich, V., Reiner, M.J., Tekle, A., and Theissen, J.
- Subjects
Ulysses (Space probe) -- Observations ,Plasma astrophysics -- Research ,Jupiter (Planet) -- Atmosphere ,Magnetosphere -- Observations -- Research ,Science and technology ,Observations ,Research - Abstract
The Unified Radio and Plasma Wave (URAP) experiment has produced new observations of the Jupiter environment, owing to the unique capabilities of the instrument and the traversal of high Jovial latitudes. Broad-band continuum radio emission from Jupiter and in situ plasma waves have proved valuable in delineating the magnetospheric boundaries. Simultaneous measurements of electric and magnetic wave fields have yielded new evidence of whistler-mode radiation within the magnetosphere. Observations of auroral-like hiss provided evidence of a Jovian cusp. The source direction and polarization capabilities of URAP have demonstrated that the outer region of the Io plasma torus supported at least five separate radio sources that reoccurred during successive rotations with a measurable corotation lag. Thermal noise measurements of the Io torus densities yielded values in the densest portion that are similar to models suggested on the basis of Voyager observations of 13 years ago. The URAP measurements also suggest complex beaming and polarization characteristics of Jovian radio components. In addition, a new class of kilometer-wavelenght striated Jovian bursts has been observed., The unique configuration, wide frequency range, and high sensitivity of the URAP instrument [1] have allowed many new observations to be made of both in situ and remote phenomena during [...]
- Published
- 1992
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