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Relevant bibliographies by topics / Magnetosphere dynamo

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Academic literature on the topic 'Magnetosphere dynamo'

Author: Grafiati

Published: 6 September 2023

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Journal articles on the topic "Magnetosphere dynamo"

1

Lopez, R. E., V. G. Merkin, and J. G. Lyon. "The role of the bow shock in solar wind-magnetosphere coupling." Annales Geophysicae 29, no. 6 (June 25, 2011): 1129–35. http://dx.doi.org/10.5194/angeo-29-1129-2011.

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Abstract. In this paper we examine the role of the bow shock in coupling solar wind energy to the magnetosphere using global magnetohydrodynamic simulations of the solar wind-magnetosphere interaction with southward IMF. During typical solar wind conditions, there are two significant dynamo currents in the magnetospheric system, one in the high-latitude mantle region tailward of the cusp and the other in the bow shock. As the magnitude of the (southward) IMF increases and the solar wind becomes a low Mach number flow, there is a significant change in solar wind-magnetosphere coupling. The high-latitude magnetopause dynamo becomes insignificant compared to the bow shock and a large load appears right outside the magnetopause. This leaves the bow shock current as the only substantial dynamo current in the system, and the only place where a significant amount of mechanical energy is extracted from the solar wind. That energy appears primarily as electromagnetic energy, and the Poynting flux generated at the bow shock feeds energy back into the plasma, reaccelerating it to solar wind speeds. Some small fraction of that Poynting flux is directed into the magnetosphere, supplying the energy needed for magnetospheric dynamics. Thus during periods when the solar wind flow has a low Mach number, the main dynamo in the solar wind-magnetosphere system is the bow shock.

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Akasofu, S. I. "The relationship between the magnetosphere and magnetospheric/auroral substorms." Annales Geophysicae 31, no. 3 (March 4, 2013): 387–94. http://dx.doi.org/10.5194/angeo-31-387-2013.

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Abstract. On the basis of auroral and polar magnetic substorm studies, the relationship between the solar wind-magnetosphere dynamo (the DD dynamo) current and the substorm dynamo (the UL dynamo) current is studied. The characteristics of both the DD and UL currents reveal why auroral substorms consist of the three distinct phases after the input power ε is increased above 1018 erg s−1. (a) The growth phase; the magnetosphere can accumulate magnetic energy for auroral substorms, when the ionosphere cannot dissipate the power before the expansion phase. (b) The expansion phase; the magnetosphere releases the accumulated magnetic energy during the growth phase in a pulse-like manner in a few hours, because it tries to stabilize itself when the accumulated energy reaches to about 1023 erg s−1. (c) The recovery phase; the magnetosphere becomes an ordinary dissipative system after the expansion phase, because the ionosphere becomes capable of dissipating the power with the rate of 1018 ~ 1019 erg s−1. On the basis of the above conclusion, it is suggested that the magnetosphere accomplishes the pulse-like release process (resulting in spectacular auroral activities) by producing plasma instabilities in the current sheet, thus reducing the current. The resulting contraction of the magnetic field lines (expending the accumulated magnetic energy), together with break down of the "frozen-in" field condition at distances of less than 10 RE, establishes the substorm dynamo that generates an earthward electric field (Lui and Kamide, 2003; Akasofu, 2011). It is this electric field which manifests as the expansion phase. A recent satellite observation at a distance of as close as 8.1 RE by Lui (2011) seems to support strongly the occurrence of the chain of processes suggested in the above. It is hoped that although the concept presented here is very crude, it will serve in providing one way of studying the three phases of auroral substorms. In turn, a better understanding of auroral substorms will also be useful in studying the magnetosphere, because various auroral activities can be the visible guide for this endeavor.

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Simon, P. A., and J. P. Legrand. "Dipole Field, Sunspot Cycle and Solar Dynamo." Symposium - International Astronomical Union 157 (1993): 97–106. http://dx.doi.org/10.1017/s0074180900173930.

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From the analysis of a series of data concerning phenomena taking place in the high corona, in the interplanetary medium and in the magnetosphere, we came to the conclusion that we have to take into consideration a two-component solar cycle in which, with a 5–6 yr delay, the cycle of the dipole component of the solar magnetic field and the following sunspot cycle are closely correlated. In order to show the new mechanisms to incorporate into a model of a two-component solar cycle, we discuss several other relevant solar data.

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Egi, Masashi, Akira Tomimatsu, and Masaaki Takahashi. "8.13. The dynamo effect in magnetohydrodynamic accretion onto a rotating black hole." Symposium - International Astronomical Union 184 (1998): 369–70. http://dx.doi.org/10.1017/s0074180900085260.

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A rotaing black hole has interesting features which can't be seen in nonrotating cases. The most characteristic one is to induce differential rotaions at angular velocity ω in inertial frames. Astrophysically it might have various impacts on its surrounding accretion plasmas. In a stationary and axisymmetric magnetohydrodynamic picture, it enables to directly extract the rotation energy of the black hole in the form of the outgoing Poynting flux. This process needs a condition ΩF(ΩH – ΩF) > 0 on the horizon r = rH, where ΩH ≡ ω|rH, and ΩF is the angular velocity of magnetosphere. However, it is not so clear how the extracted energy activates the magnetosphere. Recently, Kahnna and Camenzind (KC 1994,1995) proposed a possibility of a self-excitation mechanism of the electromagnetic fields, supported by a coupling between ω and the angular velocity of plasma Ω, through the magnetic diffusivity e of accretion plasmas. They called it ωΩ dynamo and tried to confirm this effect by numerical simulations. However no such growing cases were found in the initial conditions employed in the simulations (Brandenbrug 1996, KC 1996).

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Amory-Mazaudier, Christine. "Magnetic Signatures of Large-Scale Electric Currents in the Earth’s Environment at Middle and Low Latitudes." Atmosphere 13, no. 10 (October 17, 2022): 1699. http://dx.doi.org/10.3390/atmos13101699.

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The purpose of space weather is the systemic study of the Sun–Earth system, in order to determine the impact of solar events on the electromagnetic environment of the Earth. This article proposes a new transdisciplinary approach of the Sun–Earth system based on the universal physical process of the dynamo. The dynamo process is based on two important parameters of the different plasmas of the Sun–Earth system, the motion and the magnetic field. There are four permanent dynamos in the Sun–Earth system: the solar dynamo, the Earth dynamo, the solar wind-magnetosphere dynamo, and the ionospheric dynamo. These four permanent dynamos are part of different scientific disciplines. This transdisciplinary approach links all of these dynamos in order to understand the variations in the Earth’s magnetic field. During a magnetic disturbed period, other dynamos exist. We focused on the ionospheric disturbed dynamo generated by Joule energy dissipated in the high latitude ionosphere during magnetic storms. Joule heating disrupts the circulation of thermospheric winds and in turn generates disturbances in the Earth’s magnetic field. This systemic approach makes it possible to understand magnetic disturbances previously not well understood.

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Hellier, Coel. "Disc–magnetosphere interactions in cataclysmic variable stars." Proceedings of the International Astronomical Union 3, S243 (May 2007): 325–36. http://dx.doi.org/10.1017/s1743921307009684.

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AbstractI review, from an observational perspective, the interactions of accretion discs with magnetic fields in cataclysmic variable stars. I start with systems where the accretion flows via a stream, and discuss the circumstances in which the stream forms into an accretion disc, pointing to stars which are close to this transition. I then turn to disc-fed systems and discuss what we know about how material threads on to field lines, as deduced from the pattern of accretion footprints on the white dwarf. I discuss whether distortions of the field lines are related to accretion torques and the changing spin periods of the white dwarfs. I also review the effect on the disc–magnetosphere interaction of disc-instability outbursts. Lastly, I discuss the temporary, dynamo-driven magnetospheres thought to occur in dwarf-nova outbursts, and whether slow-moving waves are excited at the inner edges of the disc.

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Belenkaya, Elena, and Igor Alexeev. "Sliding Contacts in Planetary Magnetospheres." Symmetry 13, no. 2 (February 7, 2021): 283. http://dx.doi.org/10.3390/sym13020283.

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In the planetary magnetospheres there are specific places connected with velocity breakdown, reconnection, and dynamo processes. Here we pay attention to sliding layers. Sliding layers are formed in the ionosphere, on separatrix surfaces, at the magnetopauses and boundaries of stellar astrospheres, and at the Alfvén radius in the equatorial magnetosphere of rapidly rotating strongly magnetized giant planets. Although sliding contacts usually occur in thin local layers, their influence on the global structure of the surrounding space is very great. Therefore, they are associated with non-local processes that play a key role on a large scale. There can be an exchange between different forms of energy, a generation of strong field-aligned currents and emissions, and an amplification of magnetic fields. Depending on the conditions in the magnetosphere of the planet/exoplanet and in the flow of magnetized plasma passing it, different numbers of sliding layers with different configurations appear. Some are associated with regions of auroras and possible radio emissions. The search for planetary radio emissions is a current task in the detection of exoplanets.

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Poplavsky, A. L., O. P. Kuznechik, and N. I. Stetyukevich. "Large-scale dynamo of accretion disks around supermassive nonrotating black holes." Serbian Astronomical Journal, no. 173 (2006): 49–55. http://dx.doi.org/10.2298/saj0673049p.

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In this paper one presents an analytical model of accretion disk magnetosphere dynamics around supermassive nonrotating black holes in the centers of active galactic nuclei. Based on general relativistic equations of magneto hydrodynamics, the nonstationary solutions for time-dependent dynamo action in the accretion disks, spatial and temporal distribution of magnetic field are found. It is shown that there are two distinct stages of dynamo process: the transient and the steady-state regimes, the induction of magnetic field at t > 6:6665 x 1011GM/c3 s becomes stationary, magnetic field is located near the innermost stable circular orbit, and its value rises up to ~ 105 G. Applications of such systems with nonrotating black holes in real active galactic nuclei are discussed.

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Dimant, Y. S., and M. M. Oppenheim. "Interaction of plasma cloud with external electric field in lower ionosphere." Annales Geophysicae 28, no. 3 (March 11, 2010): 719–36. http://dx.doi.org/10.5194/angeo-28-719-2010.

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Abstract. In the auroral lower-E and upper-D region of the ionosphere, plasma clouds, such as sporadic-E layers and meteor plasma trails, occur daily. Large-scale electric fields, created by the magnetospheric dynamo, will polarize these highly conducting clouds, redistributing the electrostatic potential and generating anisotropic currents both within and around the cloud. Using a simplified model of the cloud and the background ionosphere, we develop the first self-consistent three-dimensional analytical theory of these phenomena. For dense clouds, this theory predicts highly amplified electric fields around the cloud, along with strong currents collected from the ionosphere and circulated through the cloud. This has implications for the generation of plasma instabilities, electron heating, and global MHD modeling of magnetosphere-ionosphere coupling via modifications of conductances induced by sporadic-E clouds.

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von Rekowski, B., and A. Brandenburg. "Outflows and accretion in a star-disc system with stellar magnetosphere and disc dynamo." Astronomy & Astrophysics 420, no. 1 (May 14, 2004): 17–32. http://dx.doi.org/10.1051/0004-6361:20034065.

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Dissertations / Theses on the topic "Magnetosphere dynamo"

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Morrison, Graeme A. "Thermally driven hydromagnetic dynamos." Thesis, University of Glasgow, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312706.

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Shi, Yong. "Magnetospheric current response to solar wind dynamic pressure enhancements observation and modeling results /." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1619409111&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.

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Heyner, Daniel [Verfasser], and Karl-Heinz [Akademischer Betreuer] Glaßmeier. "Das Magnetfeld des Merkur: Über den Einfluss der Magnetosphäre auf den Dynamo im Planeteninneren / Daniel Heyner ; Betreuer: Karl-Heinz Glaßmeier." Braunschweig : Technische Universität Braunschweig, 2013. http://d-nb.info/117582187X/34.

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Schrinner, Martin. "Mean-field view on geodynamo models." Doctoral thesis, [S.l.] : [s.n.], 2005. http://webdoc.sub.gwdg.de/diss/2005/schrinner.

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Parfrey, Kyle Patrick. "Simulations of Dynamic Relativistic Magnetospheres." Thesis, 2012. https://doi.org/10.7916/D8Q81M5C.

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Neutron stars and black holes are generally surrounded by magnetospheres of highly conducting plasma in which the magnetic flux density is so high that hydrodynamic forces are irrelevant. In this vanishing-inertia---or ultra-relativistic---limit, magnetohydrodynamics becomes force-free electrodynamics, a system of equations comprising only the magnetic and electric fields, and in which the plasma response is effected by a nonlinear current density term. In this dissertation I describe a new pseudospectral simulation code, designed for studying the dynamic magnetospheres of compact objects. A detailed description of the code and several numerical test problems are given. I first apply the code to the aligned rotator problem, in which a star with a dipole magnetic field is set rotating about its magnetic axis. The solution evolves to a steady state, which is nearly ideal and dissipationless everywhere except in a current sheet, or magnetic field discontinuity, at the equator, into which electromagnetic energy flows and is dissipated. Magnetars are believed to have twisted magnetospheres, due to internal magnetic evolution which deforms the crust, dragging the footpoints of external magnetic field lines. This twisting may be able to explain both magnetars' persistent hard X-ray emission and their energetic bursts and flares. Using the new code, I simulate the evolution of relativistic magnetospheres subjected to slow twisting through large angles. The field lines expand outward, forming a strong current layer; eventually the configuration loses equilibrium and a dynamic rearrangement occurs, involving large-scale rapid magnetic reconnection and dissipation of the free energy of the twisted magnetic field. When the star is rotating, the magnetospheric twisting leads to a large increase in the stellar spin-down rate, which may take place on the long twisting timescale or in brief explosive events, depending on where the twisting is applied and the history of the system. One such explosive field-expansion and reconnection event may have been responsible for the 27 August 1998 giant flare from SGR 1900+14, and the coincident sudden increase in spin period, or "braking glitch." The inner magnetospheres of relativistic compact objects are in strongly curved spacetimes. I describe the extension of the code to general-relativistic simulations, including the hypersurface foliation method and the 3+1 equations of force-free electrodynamics in curved, evolving spacetimes. A simple test problem for dynamical behavior in the Schwarzschild metric is presented, and the evolutions of the magnetospheres surrounding neutron stars and black holes, in vacuum and in force-free plasma, are compared.

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Pembroke, Asher. "A Dynamic Coupled Magnetosphere-Ionosphere-Ring Current Model." Thesis, 2013. http://hdl.handle.net/1911/72018.

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In this thesis we describe a coupled model of Earth's magnetosphere that consists of the Lyon-Fedder-Mobarry (LFM) global magnetohydrodynamics (MHD) simulation, the MIX ionosphere solver and the Rice Convection Model (RCM). We report some results of the coupled model using idealized inputs and model parameters. The algorithmic and physical components of the model are described, including the transfer of magnetic field information and plasma boundary conditions to the RCM and the return of ring current plasma properties to the LFM. Crucial aspects of the coupling include the restriction of RCM to regions where field-line averaged plasma-beta <=1, the use of a plasmasphere model, and the MIX ionosphere model. Compared to stand-alone MHD, the coupled model produces a substantial increase in ring current pressure and reduction of the magnetic field near the Earth. In the ionosphere, stronger region-1 and region-2 Birkeland currents are seen in the coupled model but with no significant change in the cross polar cap potential drop, while the region-2 currents shielded the low-latitude convection potential. In addition, oscillations in the magnetic field are produced at geosynchronous orbit with the coupled code. The diagnostics of entropy and mass content indicate that these oscillations are associated with low-entropy flow channels moving in from the tail and may be related to bursty bulk flows and bubbles seen in observations. As with most complex numerical models, there is the ongoing challenge of untangling numerical artifacts and physics, and we find that while there is still much room for improvement, the results presented here are encouraging. Finally, we introduce several new methods for magnetospheric visualization and analysis, including a fluid-spatial volume for RCM and a field-aligned analysis mesh for the LFM. The latter allows us to construct novel visualizations of flux tubes, drift surfaces, topological boundaries, and bursty-bulk flows.

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Books on the topic "Magnetosphere dynamo"

1

Liu, William, and Masaki Fujimoto, eds. The Dynamic Magnetosphere. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-0501-2.

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Parfrey, Kyle Patrick. Simulations of Dynamic Relativistic Magnetospheres. [New York, N.Y.?]: [publisher not identified], 2012.

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3

Center, Goddard Space Flight, ed. The magnetospheric constellation mission: Dynamic Response and Coupling Observatory (DRACO). [Greenbelt, Md.]: NASA, Goddard Space Flight Center, 2002.

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Planetary magnetism. New York: Springer, 2010.

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United States. National Aeronautics and Space Administration., ed. Penetration electric fields and inner magnetosphere dynamics: A model and data comparison : second annual progress report, NASW-5036 : covering period from 6 March 1997 through 5 March 1998. [Washington, DC: National Aeronautics and Space Administration, 1998.

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L, Horwitz James, Gallagher D. L, and United States. National Aeronautics and Space Administration., eds. Convection of plasmaspheric plasma into the outer magnetosphere and boundary layer region: Initial results. [Washington, D.C: National Aeronautics and Space Administration, 1998.

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Olsen, Richard Christopher. Charging characteristics of Dynamic Explorer I Retarding Ion Mass Spectrometer and the consequence for core plasma measurements. Monterey, Calif: Naval Postgraduate School, 1989.

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United States. National Aeronautics and Space Administration., ed. Modeling of the coupled magnetospheric and neutral wind dynamos: Final technical report, SRI project 4604, grant NAGW-3508. Menlo Park, CA: SRI International, 1997.

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Liu, William, and Masaki Fujimoto. Dynamic Magnetosphere. Springer Netherlands, 2016.

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Liu, William, and Masaki Fujimoto. Dynamic Magnetosphere. Springer London, Limited, 2011.

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Book chapters on the topic "Magnetosphere dynamo"

1

Potemra, T. A. "The Dynamic Magnetosphere." In Polar Cap Boundary Phenomena, 103–14. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-5214-3_9.

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Kallenrode, May-Britt. "The Dynamic Magnetosphere." In Space Physics, 255–74. Berlin, Heidelberg: Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/978-3-662-03653-2_11.

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Lavraud, Benoit, Claire Foullon, Charles J. Farrugia, and Jonathan P. Eastwood. "The Magnetopause, Its Boundary Layers and Pathways to the Magnetotail." In The Dynamic Magnetosphere, 3–28. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-0501-2_1.

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Jordanova, Vania K. "Self-Consistent Simulations of Plasma Waves and Their Effects on Energetic Particles." In The Dynamic Magnetosphere, 189–99. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-0501-2_10.

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Antonova, Elizaveta E., Igor P. Kirpichev, Ilya L. Ovchinnikov, Maria S. Pulinets, Svetlana S. Znatkova, Ksenia G. Orlova, and Marina V. Stepanova. "Topology of High-Latitude Magnetospheric Currents." In The Dynamic Magnetosphere, 201–10. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-0501-2_11.

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Balasis, Georgios, Ioannis A. Daglis, Anastasios Anastasiadis, and Konstantinos Eftaxias. "Detection of Dynamical Complexity Changes in Dst Time Series Using Entropy Concepts and Rescaled Range Analysis." In The Dynamic Magnetosphere, 211–20. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-0501-2_12.

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Menk, Frederick W. "Magnetospheric ULF Waves: A Review." In The Dynamic Magnetosphere, 223–56. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-0501-2_13.

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Pilipenko, V., E. Fedorov, B. Heilig, M. J. Engebretson, P. Sutcliffe, and H. Luehr. "ULF Waves in the Topside Ionosphere: Satellite Observations and Modeling." In The Dynamic Magnetosphere, 257–69. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-0501-2_14.

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Chaston, Christopher C., K. Seki, T. Sakanoi, Kazushi Asamura, and M. Hirahara. "Evidence for a Multi-scale Aurora." In The Dynamic Magnetosphere, 271–80. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-0501-2_15.

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Yau, Andrew W., W. K. Peterson, and Takumi Abe. "Influences of the Ionosphere, Thermosphere and Magnetosphere on Ion Outflows." In The Dynamic Magnetosphere, 283–314. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-0501-2_16.

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Conference papers on the topic "Magnetosphere dynamo"

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Chamati, Maria, and Borislav Andonov. "Pc5 PULSATIONS OBSERVED DURING THE GEOMAGNETIC STORM ON 12 MAY 2021." In 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022/1.1/s05.063.

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The study of ultra-low frequency (ULF) waves and geomagnetic pulsations plays an important role in better understanding the mechanisms of their generation and spread in the magnetosphere and on the ground. The magnetospheric ULF waves, which provide useful information about the conditions in the solar wind and in the magnetosphere, can be detected on the ground by different types of magnetometers and recorded as geomagnetic pulsations � continuous and irregular. This paper aims to study the characteristics of Pc5 geomagnetic continuous pulsations recorded at mid latitudes during the strong geomagnetic storm (Kp =7) that occurred on May 12, 2021. The sets of time series of data at sampling period 1s, recorded along the three geomagnetic directions (X, Y and Z), are shown and analyzed. A spectral analysis, based on the Morlet Wavelet transform, is applied. It shows powerful geomagnetic disturbances in the Pc5 band (1.7-6.7 mHz) in two-time intervals: 00-02 UTC- before the beginning of the storm and 10-15 UTC- during the storm. Furthermore, the Fast Fourier Transform (FFT) band pass filter is applied to the data series, and Pc5 pulsations are shown. It was concluded that their emergence was correlated with the dynamics of changes in the interplanetary magnetic field (IMF) Bz component, solar wind plasma speed, and flow dynamic pressure.

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Chamati, Maria. "CHARACTERISTICS OF Pc5 PULSATIONS ACTIVITY AT MID LATITUDES DURING DECEMBER 2019." In 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022/1.1/s05.059.

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Magnetospheric pulsations and the mechanisms underlying their generation are topics under active studies. The Pc5 (f =1.7�6.7 mHz) geomagnetic continuous pulsations, recorded at mid latitudes (L =1.6) during December 2019, with a low level of geomagnetic activity, are analyzed and discussed in this paper. The data sets of the series on geomagnetic field variations recorded at Panagjuriste Geomagnetic Observatory in Bulgaria are analyzed. The spectral characteristics of the pulsations were determined by Continuous Wavelet Analysis (CWT). It is demonstrated that Pc5 pulsation activity appears with all ranges of periods (140-600s) on December 6, 8, and 18, 2019, at time intervals of 02-17 UTC, 14-20 UTC, and 00-16 UTC, respectively. Then, the solar wind (SW) plasma speed, the flow dynamic pressure, and the geomagnetic index Kp are computed for every case of recorded Pc5 pulsations. It is suggested that recorded continuous pulsations in the Pc5 range are due to step-like or sudden increases in solar wind oscillations and variations of the flow dynamic pressure, which precede the appearance of pulsations and drive compressional magnetic field variations in the magnetosphere.

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Kleimenova, N. G., J. Manninen, T. Turunen, L. I. Gromova, Yu V. Fedorenko, A. S. Nikitenko, and O. M. Lebed. "Unexpected high-frequency “birds”-type VLF emissions." In Physics of Auroral Phenomena. FRC KSC RAS, 2020. http://dx.doi.org/10.37614/2588-0039.2020.43.008.

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The new typeof daytime natural VLF whistler mode emissions of the magnetospheric origin was recently found in the VLF observations at Kannuslehto station (L ~ 5.5) in Northern Finland.These VLF events occurred at the frequencies above 4-5 kHzeven up to 15 kHz. Here we present the different spectra of this peculiar daytime high-frequency VLF emissions observed under quiet geomagnetic conditions at auroral latitudes at Kannuslehto (Finland) and Lovozero (Russia) stations. These high-frequency waves cannot be attributed to typical well known VLF chorus and hiss. They became visible on the spectrograms only after the filtering out sferics originating by the lightning discharges and hiding all natural high-frequency signals. After this filtering, it was found a large collection of different natural VLF signals observed as a sequence of right-polarized short (less than 1-2 minutes) patches at frequencies above 4-5 kHz, i.e. at higher frequencythan a half the equatorial electron gyrofrequency at the L-shell of Kannuslehto and Lovozero. These emissions were called “birds” due to their chirped sounds. It was established that the “birds” are typically occur during the daytime only under quiet space weather conditions. But in this time, small magnetic substorms were could be observed in the night sector of the Earth. Here we also show the recently observed series of the “bird-mode” emissions with various bizarre quasi-periodic dynamic spectra, sometimes consisting of two (and even more) frequency bands. The “birds” occur simultaneously at Kannuslehto and Lovozero with similar spectral structure demonstrating their common source. It seems that the “birds” emissions are generated deep inside the magnetosphere at the low L-shells. But the real nature, the generation region and propagation behavior of these VLF emissions remain still unknown. Moreover, nobody can explain how the waves could reach the ground at the auroral latitudes like Kannuslehto and Lovozero as well as which magnetospheric driver could generate this very complicated spectral feature of the emissions.

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Mao, Yao-Ting, David Auslander, David Pankow, and John Sample. "Estimating Angular Velocity, Attitude Orientation With Controller Design for Three Units CubeSat." In ASME 2014 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/dscc2014-5895.

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CINEMA (CubeSat for Ions, Neutrals, Electrons and MAgneticfields) will image energetic neutral atoms (ENAs) in the magnetosphere, and make measurements of electrons, ions, and magnetic fields at high latitudes. To satisfy the mission requirements, the three unit cubesat was designed. The spin axis needs to be in the ecliptic normal and the spin rate needs to be 4 rpm. The only power source for CINEMA is the solar panels. External torques are generated by an orthogonal pair of coils acting with the earths magnetic field. This paper provides the control strategy, given the limited power and available sensors, to optimize the convergence of the spin and attitude control.

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Krimigis, Stamatios M., Dimitris Vassiliadis, Shing F. Fung, Xi Shao, Ioannis A. Daglis, and Joseph D. Huba. "Saturn’s magnetosphere: An example of dynamic planetary systems." In MODERN CHALLENGES IN NONLINEAR PLASMA PHYSICS: A Festschrift Honoring the Career of Dennis Papadopoulos. AIP, 2011. http://dx.doi.org/10.1063/1.3544327.

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Shen, Xiaochen, Quanqi Shi, Anmin Tian, Suiyan Fu, Qiugang Zong, and Zuyin Pu. "Initial responses of magnetospheric plasma flows to the dynamic pressure enhancements." In 2014 XXXIth URSI General Assembly and Scientific Symposium (URSI GASS). IEEE, 2014. http://dx.doi.org/10.1109/ursigass.2014.6929925.

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Tian, Anmin, Xiaochen Shen, and Quanqi Shi. "Characteristics of dayside magnetospheric flows during solar wind dynamic pressure pulse." In 2014 XXXIth URSI General Assembly and Scientific Symposium (URSI GASS). IEEE, 2014. http://dx.doi.org/10.1109/ursigass.2014.6929930.

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Despirak, I. V., A. A. Lubchich, and N. G. Kleimenova. "Several special conditions in the solar wind fora supersubstorm appearance." In Physics of Auroral Phenomena. FRC KSC RAS, 2020. http://dx.doi.org/10.37614/2588-0039.2020.43.001.

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Analysis of the space weather conditions associated with supersubstorms (SSS) was carried out. Two magnetic storms, on 11 April and on 18 April 2001 have been studied and compared. During the first storm, there were registered twoevents of the supersubstorms with intensity of the SML index ~2000-3000 nT, whereas during the second storm there were observed two intense substorms with SML ~ 1500 nT. Solar wind conditions before appearance of the SSSs and intense substorms were compared. For this purpose, the OMNI data base, the catalog of large-scale solar wind phenomena and the data from the magnetic ground-based stations of the SuperMAG network (http://supermag.jhuapl.edu/) were combined. It was shown that the onsets of the SSS event were preceded by strong jumps in the dynamic pressure and density of the solar wind, which were observed against the background of the high solar wind speed and high values of the southern ВZcomponent of the IMF. Comparison with the usual substorms showed thatsome solar wind parameters were higher before SSSs, then before usual substorms: the dynamic pressure, the speed and the magnitude of IMF. On the other hand, the PC index values was the same for these all substorms, that leads to the conclusion about the possible independence of SSS appearance on the level of solar energy penetrated to the magnetosphere.

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Reports on the topic "Magnetosphere dynamo"

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BARKHATOV, NIKOLAY, and SERGEY REVUNOV. A software-computational neural network tool for predicting the electromagnetic state of the polar magnetosphere, taking into account the process that simulates its slow loading by the kinetic energy of the solar wind. SIB-Expertise, December 2021. http://dx.doi.org/10.12731/er0519.07122021.

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The auroral activity indices AU, AL, AE, introduced into geophysics at the beginning of the space era, although they have certain drawbacks, are still widely used to monitor geomagnetic activity at high latitudes. The AU index reflects the intensity of the eastern electric jet, while the AL index is determined by the intensity of the western electric jet. There are many regression relationships linking the indices of magnetic activity with a wide range of phenomena observed in the Earth's magnetosphere and atmosphere. These relationships determine the importance of monitoring and predicting geomagnetic activity for research in various areas of solar-terrestrial physics. The most dramatic phenomena in the magnetosphere and high-latitude ionosphere occur during periods of magnetospheric substorms, a sensitive indicator of which is the time variation and value of the AL index. Currently, AL index forecasting is carried out by various methods using both dynamic systems and artificial intelligence. Forecasting is based on the close relationship between the state of the magnetosphere and the parameters of the solar wind and the interplanetary magnetic field (IMF). This application proposes an algorithm for describing the process of substorm formation using an instrument in the form of an Elman-type ANN by reconstructing the AL index using the dynamics of the new integral parameter we introduced. The use of an integral parameter at the input of the ANN makes it possible to simulate the structure and intellectual properties of the biological nervous system, since in this way an additional realization of the memory of the prehistory of the modeled process is provided.

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Sonnerup, Bengt U., and William Lotko. Dynamic Processes at the Outer Boundary of the Magnetosphere, Including Coupling to the Ionosphere. Fort Belvoir, VA: Defense Technical Information Center, April 1994. http://dx.doi.org/10.21236/ada282038.

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