Limpar
78 resultados

Acesso aberto

Tipo do recurso

Ano de criação

Produção nacional

Revisado por pares

Áreas

Idioma

Editores

Jornais Acesso aberto

Business Summary, Lynne Dodd, Frances Gibb, Legal Affairs Correspondent, Barry Pickthall Pusan, Christopher Warman, Property Correspondent, Daniel Ward, Motor Industry Correspondent, Neil Watson, William Rodney, Dean, Andrew Longmore, Cliff Feltham, John Jacobs, Michael Stevenson, Alfred Brown, Richard Evans, Media Editor, Carol Leonard, Harry Eyres, Colin Narbrough, Joe Joseph, Mitchell Platts, Mitchell Platts, Golf Correspondent, John Rae, Peter Davenport, Michael Tate, Jill Sherman, Social Services Correspondent, Richard Ford Political Correspondent, Peter Waymark, Robin Young, Martin Cropper, David Smith Economics Correspondent, Martin Fletcher, Political Reporter, Arthur W. J. G. Ord-Hume, Editor, Charles Bremner, Woodrow Wyatt, Richard Thomson, Banking Correspondent, Joan S. R. Oliver, Harvey Elliott, Air Correspondent, Iain Vallance, Robert Kirley, Sydney Friskin, Nicholas Harling, Dennis Signy, David Miller, Nigel Andrew, Mitchell Platts Golf Correspondent, (Michael Phillips), Josephine Fairley, Philip Hebbert, Victory McKee, Sarah Jane Checkland, Art Sales Correspondent, L. Boreland, Alison Eadie, Anthony Hodges, Dennis Shaw, Nicholas Beeston, Peter Dear and Jane Rackham, Steve Acteson, Andrew McEwen, Diplomatic Correspondent, John Cooney, Alexandra Jackson, Alice Thomas Ellis, Peter Bryan, Norman Lebrecht, Stewart Tendler, Crime Reporter, Flowers, Vice-Chancellor, David Young, Energy Correspondent, Martin Searby, Irving Wardle, Marcel Berlins, Ian Ross, Basil Boothroyd, Sarah Thompson Education Reporter, Bryan Appleyard, David Sapsted, Kenneth Fleet, Christopher Walker, Carol Ferguson, Edward Townsend, Industrial Correspondent, Brian Moore, Anthony Parsons, Graham Searjeant, Financial Editor, Clive White, Liz Smith, Michael Hornsby, Michael Seely, David Gollob, Boyd-Carpenter, Michael Clark and Geoffrey Foster, Antonia Fraser, Barry Wood, Ian Stafford, David Sinclair, Tim Jones, George Chesterton, Michael Binyon and Zoriana Pysariwsky, John Young Agriculture Correspondent, Robert Fisk, Michael Evans Defence Correspondent, Pearce Wright, Science Editor, Frank Field, Delia Burton, P. Neil Garrard, Jan Raath, David Hands, Rugby Correspondent, Mary Dejevsky, Stuart Jones, Football Correspondent, Kenneth Fleet Executive Editor,

... Clear on Education Charisma in the United States Anomaly in child benefit cuts aim 'Forgotten' command Ethnic education South of the river Roots of royalty Second-hand ...

1987 - Gale Group | TDA

Artigo Acesso aberto Revisado por pares

Pablo S. Moya, V. A. Pinto, D. G. Sibeck, S. G. Kanekal, D. N. Baker,

Abstract Using Van Allen Probes Energetic Particle, Composition, and Thermal Plasma‐Relativistic Electron‐Proton Telescope (ECT‐REPT) observations, we performed a statistical study on the effect of geomagnetic storms on relativistic electrons fluxes in the outer radiation belt for 78 storms between September 2012 and June 2016. We found that the probability of enhancement, depletion, and no change in flux values depends strongly on L and energy. Enhancement events are more common for ∼2 MeV electrons ...

Tópico(s): Earthquake Detection and Analysis

2017 - Wiley | Journal of Geophysical Research Space Physics

Artigo Acesso aberto Revisado por pares

Artem Smirnov, Max Berrendorf, Yuri Shprits, E. A. Kronberg, Hayley Allison, Nikita Aseev, Irina Zhelavskaya, Steven K. Morley, G. D. Reeves, Matthew Carver, Frederic Effenberger,

Abstract The radiation belts of the Earth, filled with energetic electrons, comprise complex and dynamic systems that pose a significant threat to satellite operation. While various models of electron flux both for low and relativistic energies have been developed, the behavior of medium energy (120–600 keV) electrons, especially in the MEO region, remains poorly quantified. At these energies, electrons are driven by both convective and diffusive transport, and their prediction usually requires sophisticated ...

Tópico(s): Geomagnetism and Paleomagnetism Studies

2020 - American Geophysical Union | Space Weather

Artigo Revisado por pares

B.E. Carlsten, P. Colestock, G. Cunningham, Gian Luca Delzanno, E. E. Dors, Michael Holloway, C. A. Jeffery, John Lewellen, Quinn R. Marksteiner, Dinh C. Nguyen, G. D. Reeves, Kevin Shipman,

Energetic electrons can be trapped in Earth's magnetic field, forming the radiation belts (also known as the Van Allen Belts). These electrons, which can originate from the solar wind or a high-altitude nuclear explosion (HANE), have the potential to damage satellites in low-Earth orbit (LEO). For example, in 1962, the U.S. detonated a nuclear device at an altitude of about 400 km in the Starfish experiment. The resulting enhancement of the radiation belts disabled several satellites within a few months ...

Tópico(s): Solar and Space Plasma Dynamics

2019 - Institute of Electrical and Electronics Engineers | IEEE Transactions on Plasma Science

Artigo Revisado por pares

J. A. Sauvaud, Thomas Moreau, R. Maggiolo, J. P. Treilhou, C. Jacquey, A. Cros, J. Coutelier, Jean‐Noël Rouzaud, E. Penou, M. Gangloff,

This paper gives a description and the first results of the electron spectrometer placed onboard the Demeter satellite. This detector with a large geometrical factor is aimed to measure trapped electron fluxes in the energy range from 70 keV to about 0.8 MeV and to provide information on the electron fluxes between 0.8 and 2.5 MeV. The energy resolution, better than 10 keV, and the 256 energy channels allow to obtain insights on the radiation belt structure. The data received during 2004 show for ...

Tópico(s): Geomagnetism and Paleomagnetism Studies

2006 - Elsevier BV | Planetary and Space Science

Artigo Acesso aberto

Hiroshi Oya, Tadatoshi Takahashi, Akira Morioka,

... 406kHz reveals the ion sheath thickness surrounding the probe. In the region of the South Atlantic anomaly of the geomagnetic field, quick changes of the ion sheath capacitance have been observed indicating charging up of the probe. These quick changes are separated into two types; the first is the quick sharp variation and the second is the gradual variation. The sharp variation of the sheath capacitance value is disclosed to be triggered by the telemetry radio wave in the region of the South Atlantic anomaly.

Tópico(s): Solar and Space Plasma Dynamics

1979 - Society of Geomagnetism and Earth, Planetary and Space Sciences | Journal of geomagnetism and geoelectricity

Artigo Revisado por pares

M. de Soria‐Santacruz Pich, Insoo Jun, Robin W. Evans,

... AP8. The relatively short duration of Van Allen Probes and Jason‐2 missions means that their measurements are most certainly the result of specific climatological conditions. In low Earth orbit (LEO), the Jason‐2 proton flux is better reproduced by AP8 compared to AP9, while the POES electron data are well enveloped by AE9 5th and 95th percentiles. The shape of the South Atlantic anomaly (SAA) from Jason‐2 data is better captured ...

Tópico(s): Astro and Planetary Science

2017 - American Geophysical Union | Space Weather

Artigo Revisado por pares

M. I. Panasyuk, М. В. Подзолко, A. S. Kovtyukh, I. A. Brilkov, N. A. Vlasova, V. V. Kalegaev, V. I. Osedlo, V. I. Tulupov, I. V. Yashin,

Tópico(s): Geomagnetism and Paleomagnetism Studies

2017 - Pleiades Publishing | Cosmic Research

Artigo Acesso aberto Revisado por pares

Viviane Pierrard, Edith Botek, J.‐F. Ripoll, G. Cunningham,

Abstract Electron flux variations for E > 500 keV during geomagnetic storms are investigated using the Energetic Particle Telescope (EPT). This detector launched in May 2013 on board the satellite PROBA‐V at an altitude of 820 km was designed to provide uncontaminated spectra of electrons, protons, and alpha particles. Electron flux dropout events are observed during the main phase of each storm and even during substorms: a rapid reduction of the electron flux is noted throughout the outer electron ...

Tópico(s): Earthquake Detection and Analysis

2020 - Wiley | Journal of Geophysical Research Space Physics

Artigo Acesso aberto Revisado por pares

Thomas Berger, S. Burmeister, Daniel Matthiä, Bartos Przybyla, Günther Reitz, P. Bilski, Michael Hajek, Lembit Sihver, Julianna Szabó, Iva Ambrožová, F. Vanhavere, Ramona Gaza, E. Semones, E.G. Yukihara, E. R. Benton, Yukio Uchihori, Satoshi Kodaira, Hisashi Kitamura, Matthias Boehme,

The natural radiation environment in Low Earth Orbit (LEO) differs significantly in composition and energy from that found on Earth. The space radiation field consists of high energetic protons and heavier ions from Galactic Cosmic Radiation (GCR), as well as of protons and electrons trapped in the Earth's radiation belts (Van Allen belts). Protons and some heavier particles ejected in occasional Solar Particle Events (SPEs) might in addition contribute to the radiation exposure in LEO. All sources ...

Tópico(s): Astro and Planetary Science

2017 - EDP Open | Journal of Space Weather and Space Climate

Artigo Acesso aberto Revisado por pares

Viviane Pierrard, Graciela López Rosson,

Abstract. With the energetic particle telescope (EPT) performing with direct electron and proton discrimination on board the ESA satellite PROBA-V, we analyze the high-resolution measurements of the charged particle radiation environment at an altitude of 820 km for the year 2015. On 17 March 2015, a big geomagnetic storm event injected unusual fluxes up to low radial distances in the radiation belts. EPT electron measurements show a deep dropout at L > 4 starting during the main phase of the storm, ...

Tópico(s): Solar and Space Plasma Dynamics

2016 - Copernicus Publications | Annales Geophysicae

Artigo Acesso aberto Revisado por pares

Jiyao Xu, Zhaohai He, D. N. Baker, I. Roth, Chi Wang, S. G. Kanekal, A. N. Jaynes, Xiao Liu,

Abstract High‐energy trapped particles in the radiation belts constitute potential threats to the functionality of satellites as they enter into those regions. In the inner radiation belt, the characteristics of high‐energy (>20 MeV) protons variations during geomagnetic activity times have been studied by implementing 4‐year (2013–2016) observations of the Van Allen probes. An empirical formula has been used to remove the satellite orbit effect, by which proton fluxes have been normalized to the geomagnetic ...

Tópico(s): Geomagnetism and Paleomagnetism Studies

2019 - Wiley | Journal of Geophysical Research Space Physics

Artigo Acesso aberto Revisado por pares

R. B. Horne, S. A. Glauert, Nigel P. Meredith, D. Boscher, Vincent Maget, D. Heynderickx, David Pitchford,

Satellites can be damaged by high energy charged particles in the Earth's radiation belts and during solar energetic particle (SEP) events. Here we review the growing reliance on satellite services, new vulnerabilities to space weather, and previous events that have led to loss of service. We describe a new European system to forecast the radiation belts up to 3 h ahead, which has three unique features: first, it uses physics‐based models, which include wave‐particle interactions; second, it provides ...

Tópico(s): Earthquake Detection and Analysis

2013 - American Geophysical Union | Space Weather

Artigo Revisado por pares

А. О. Конради, G. D. Badhwar, L.A. Braby,

Active instruments consisting of a tissue equivalent proportional counter (TEPC) and a proton and heavy ion detector (PHIDE) have been carried on a number of Space Shuttle flights. These instruments have allowed us to map out parts of the South Atlantic Particle Anomaly (SAA) and to compare some of its features with predictions of the AP-8 energetic proton flux models. We have observed that consistent with the generally observed westward drift of the surface features of the terrestrial magnetic field ...

Tópico(s): Gamma-ray bursts and supernovae

1994 - Elsevier BV | Advances in Space Research

Artigo Revisado por pares

Tsvetan Dachev,

Two Liulin type spectrometers performed measurements of the energetic particles flux outside the International Space Station (ISS) in 3 long-term periods between 2008 and 2016. The linear regression analysis is performed of 1053 averaged per day South-Atlantic anomaly (SAA) proton flux measurements from the daily Dst index. The data reveal that the SAA flux dependence from the Joule heating in the high latitudes and respectively from the neutral atmosphere density, isn't observed only in the time ...

Tópico(s): Atmospheric Ozone and Climate

2018 - Elsevier BV | Journal of Atmospheric and Solar-Terrestrial Physics

Artigo Revisado por pares

Timo Asikainen, К. Мурсула,

Here we study energetic electron fluxes in the inner radiation belt (L<2), especially within the South Atlantic Anomaly (SAA) region during a period of a few months using data from the low-altitude NOAA-15 and 16 satellites. Observations by these two spacecraft can yield long-term measurements of energetic electron fluxes at four different local time sectors. We discuss the time development as well as local time and longitude dependence of energetic electron fluxes around the magnetic equator at L< ...

Tópico(s): Geomagnetism and Paleomagnetism Studies

2007 - Elsevier BV | Journal of Atmospheric and Solar-Terrestrial Physics

Artigo Revisado por pares

L. V. Tverskaya,

Tópico(s): Earthquake Detection and Analysis

2010 - Pleiades Publishing | Moscow University Physics Bulletin

Artigo Acesso aberto Revisado por pares

M.‐C. Fok, R. B. Horne, Nigel P. Meredith, S. A. Glauert,

A data‐driven physical model of the energetic electrons in the Earth's radiation belts, called the Radiation Belt Environment (RBE) model, has been developed to understand Earth's radiation belt dynamics and to predict the radiation conditions found there. This model calculates radiation belt electron fluxes from 10 keV to 6 MeV in the inner magnetosphere. It takes into account the realistic, time‐varying magnetic field and considers effects of wave‐particle interactions with whistler mode chorus ...

Tópico(s): Geomagnetism and Paleomagnetism Studies

2008 - American Geophysical Union | Journal of Geophysical Research Atmospheres

Artigo Revisado por pares

Ц. Дачев, Jordanka Semkova, Yu.N. Matviichuk, B.T. Tomov, R. Koleva, P. Baynov, V. M. Petrov, Vyacheslav Shurshakov, Yu. V. Ivanov,

Measurements on board the Mir space station have been used to study the dose rate and the particle flux distribution in the inner magnetosphere. The measurements have been performed with the Bulgarian-Russian dosimeter-radiometer Liulin. The paper concentrates on the dynamics of the observed "new" and "second" maxima which were created after Solar Proton Events (SPE) in the 1989-1994 time. The "second" belt was first observed after the SPE on October 20, 1989, and the last observation was after the ...

Tópico(s): Geomagnetism and Paleomagnetism Studies

1998 - Elsevier BV | Advances in Space Research

Artigo Revisado por pares

J. A. Sauvaud, M. Walt, D. Delcourt, C. Benoist, E. Penou, Yue Chen, C. T. Russell,

Geomagnetic storms are frequently associated with the formation of multiple bands of energetic electrons inside the inner radiation belt at L = 1.1–1.9 and with prominent energy structures of protons inside the slot region at L = 2.2–3.5. These structures typically from 100 keV up to the MeV range result from coherent interactions of energetic particles with quasi‐monochromatic ultra‐low frequency (ULF) waves. These waves are induced by magnetospheric changes due to the arrival of dense solar material ...

Tópico(s): Earthquake Detection and Analysis

2013 - Wiley | Journal of Geophysical Research Space Physics

Artigo Revisado por pares

Masataka Kinoshita, Osamu Matsubayashi, Richard P. Von Herzen,

... 26°0′N, 44°49′W) of Mid‐Atlantic Ridge. Two geothermal probes made reliable measurements. Six transient anomalies in subbottom temperatures were detected 20 m south of the central black‐smoker complex (CBC), having ...

Tópico(s): Hydrocarbon exploration and reservoir analysis

1996 - American Geophysical Union | Geophysical Research Letters

Artigo Acesso aberto Revisado por pares

S. Benck, M. Cyamukungu, J. Cabrera, L. Mazzino, Viviane Pierrard,

The evaluation of the radiation hazards on components used in space environment is based on the knowledge of the radiation level encountered on orbit. The models that are widely used to assess the near-Earth environment for a given mission are empirical trapped radiation models derived from a compilation of spacecraft measurements. However, these models are static and hence are not suited for describing the short timescale variations of geomagnetic conditions. The transient observation-based particle ( ...

Tópico(s): Astro and Planetary Science

2013 - EDP Open | Journal of Space Weather and Space Climate

Artigo Revisado por pares

K. Bullough, A.R.L. Tatnall, M. Denby,

Tópico(s): Lightning and Electromagnetic Phenomena

1976 - Nature Portfolio | Nature

Artigo Revisado por pares

T. Whyntie, M. Harrison,

The Langton Ultimate Cosmic ray Intensity Detector (LUCID) experiment is a satellite-based device that uses five Timepix hybrid silicon pixel detectors to make measurements of the radiation environment at an altitude of approximately 630 km, i.e. in Low Earth Orbit (LEO) . The experiment launched aboard Surrey Satellite Technology Limited's (SSTL's) TechDemoSat-1 on Tuesday the 8th of July 2014. The Timepix detectors, developed by the Medipix2 Collaboration, are arranged to form the five sides of a cube ...

Tópico(s): Dark Matter and Cosmic Phenomena

2015 - Institute of Physics | Journal of Instrumentation

Artigo Acesso aberto Revisado por pares

O. Adriani, G. C. Barbarino, G. A. Bazilevskaya, R. Bellotti, M. Boezio, É. A. Bogomolov, M. Bongi, V. Bonvicini, S. Bottai, A. Bruno, F. Cafagna, D. Campana, R. Carbone, P. Carlson, M. Casolino, G. Castellini, C. De Donato, C. De Santis, Nicola Simone, V. Di Felice, V. Formato, A. M. Galper, A. V. Karelin, S. V. Koldashov, S. Koldobskiy, S. Y. Krutkov, А. Н. Квашнин, A. Leonov, V. Malakhov, L. Marcelli, M. Martucci, A. G. Mayorov, W. Menn, М. Мерге, V. V. Mikhailov, E. Mocchiutti, A. Monaco, N. Mōri, R. Munini, G. Osteria, F. de Palma, B. Panico, P. Papini, M. Pearce, P. Picozza, M. Ricci, S. Ricciarini, R. Sarkar, V. Scotti, M. Simon, R. Sparvoli, П. Спиллантини, Y. I. Stozhkov, A. Vacchi, E. Vannuccini, G. Vasilyev, S. A. Voronov, Y. T. Yurkin, G. Zampa, N. Zampa, V. G. Zverev,

We report an accurate measurement of the geomagnetically trapped proton fluxes for kinetic energy above > 70 MeV performed by the PAMELA mission at low Earth orbits (350-610 km). Data were analyzed in the frame of the adiabatic theory of charged particle motion in the geomagnetic field. Flux properties were investigated in detail, providing a full characterization of the particle radiation in the South Atlantic Anomaly region, including locations, energy spectra and pitch angle distributions. PAMELA ...

Tópico(s): Astro and Planetary Science

2015 - IOP Publishing | The Astrophysical Journal Letters

Artigo Acesso aberto Revisado por pares

F. Němec, O. Santolı́k, G. B. Hospodarsky, Mychajlo Hajoš, A. G. Demekhov, W. S. Kŭrth, M. Parrot, D. P. Hartley,

... significantly less frequent at the longitudes of the South Atlantic Anomaly. Further, while the events observed by Van Allen Probes are smoothly distributed over seasons with only mild ...

Tópico(s): Geomagnetism and Paleomagnetism Studies

2020 - Wiley | Journal of Geophysical Research Space Physics

Artigo Acesso aberto Revisado por pares

Rongxin Tang, Yuhao Tao, Jiahao Li, Zhou Chen, Xiaohua Deng, Haimeng Li,

Abstract High energy electrons in planetary radiation belts are a major threat to satellites and communications in deep space applications. In order to predict the variations of energetic electron fluxes for different energy channels, we proposed a new ensemble machine leaning model for differential electron flux from 30 keV to 4 MeV in the Earth's radiation belts based on the RBSP‐A observation data from March 2013 to December 2017. The deep neural network (DNN), the convolutional neural network ( ...

Tópico(s): Geomagnetism and Paleomagnetism Studies

2022 - American Geophysical Union | Space Weather

Artigo Revisado por pares

Z. Y. Pu, Lun Xie, Wenpin Jiao, S. Y. Fu, Xuan Fang, Qiugang Zong, D. Heynderickx,

To investigate long-term variations of the inner zone high-energy proton environment at low orbits, we developed the drift shell tracing (DST) approach by using the adiabatic approximation of charged particle motion with the NASA standard radiation models as reference states. The DST results show that over the past three decades fluxes of high-energy protons at altitudes ∼ 1000 km in the South Atlantic Anomaly (SAA) noticeably increased and the centre region of the proton SAA apparently moved westward ...

Tópico(s): Astro and Planetary Science

2005 - Elsevier BV | Advances in Space Research

Artigo Revisado por pares

Graciela López Rosson, Viviane Pierrard,

Proton and electron spectra observed by the Energetic Particle Telescope (EPT) on board the ESA satellite PROBA-V have been investigated at different locations in the South Atlantic Anomaly (SAA). The EPT spectrometer provides high-resolution measurements of the charged particle radiation environment in space performing with direct electron, proton and heavy ion discrimination. Dividing the SAA into 5 different bins of 5° × 5° each one for protons, we obtain that the average proton spectra have often ...

Tópico(s): Astro and Planetary Science

2017 - Elsevier BV | Advances in Space Research