Eruptive Solar Flares
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Eruptive Solar Flares
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Author : Zdeněk Švestka
language : en
Publisher: Springer
Release Date : 1992
Eruptive Solar Flares written by Zdeněk Švestka and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 1992 with Science categories.
Predictions Of Reconnected Flux Energy And Helicity In Eruptive Solar Flares
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Author : Maria Dmitriyevna Kazachenko
language : en
Publisher:
Release Date : 2010
Predictions Of Reconnected Flux Energy And Helicity In Eruptive Solar Flares written by Maria Dmitriyevna Kazachenko and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with Magnetic reconnection categories.
In order to better understand the solar genesis of interplanetary magnetic clouds, I model the magnetic and topological properties of several large eruptive solar flares and relate them to observations. My main hypothesis is that the flux ropes ejected during eruptive solar flares are the result of a sequence of magnetic reconnections. To test this hypothesis, I use the three-dimensional Minimum Current Corona model of flare energy storage (Longcope, 1996) together with pre-flare photospheric magnetic field and flare ribbon observations to predict the basic flare properties: reconnected magnetic flux, free energy, and flux rope helicity. Initially, the MCC model was able to quantify the properties of the flares that occur in active regions with only photospheric shearing motions. Since rotating motions may also play a key role in the flare energetics, I develop a method for including both shearing and rotating motions into the MCC model. I use this modified method to predict the model flare properties and then compare them to the observed quantities. Firstly, for two flares in active regions with fast rotating sunspots, I find that the relative importance of shearing and rotation to those flares depends critically on their location within the parent active region topology. Secondly, for four flares analyzed with the MCC model (three flares described here and one flare described in Longcope et al. (2007)), I find that the modeled flare properties agree with the observed properties within the uncertainties of the methods used. This agreement compels me to believe that the magnetic clouds associated with these four solar flares are formed by low-corona magnetic reconnection during the eruption as modeled by the MCC model, rather than eruption of pre-existing structures in the corona or formation in the upper corona with participation of the global magnetic field. I note that since all four flares occurred in active regions without significant pre-flare flux emergence and/or cancellation, the energy and helicity values I find are due primarily to shearing and rotating motions, which are sufficient to account for the observed flare energy and MC helicity.
Eruptive Solar Flares
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Author : Zdenek Svestka
language : en
Publisher: Springer
Release Date : 2014-03-12
Eruptive Solar Flares written by Zdenek Svestka and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014-03-12 with Science categories.
This is an exhaustive survey of present-day solar research including both theory and observations. It deals with eruptive flares, filament eruption in x-rays and radio waves, energy release and transport, and terrestrial response to solar flares. Details of the most recent SOLAR-A project (launched shortly after the conference) are also presented.
Solar Flares And Collisions Between Current Carrying Loops
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Author : Jun-Ichi Sakai
language : en
Publisher: Springer Science & Business Media
Release Date : 2012-12-06
Solar Flares And Collisions Between Current Carrying Loops written by Jun-Ichi Sakai and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-12-06 with Science categories.
In this volume we compare modem observations of solar flares with results from recent theoretical research and simulation studies on current-carrying loops and their interaction. These topics have undergone rapid developments in the course of recent years. Observational results by X-ray monitoring and imaging spacecraft in the seventies and by dedicated imaging instrumentation in the satellites Solar Max imum Mission and Hinotori, launched 1980 and 1981, have shown the importance of X-ray imaging for understanding the ignition processes of solar flares. Such observations, in tum, stimulated theoretical studies, centered around the flux-tube concept. The classical idea that flares originate by interaction of current-carrying loops was developed and proved to be promising. Concepts on reconnection and coalescence of flux tubes were developed, and their consequences studied. The Yohkoh spacecraft, launched 1991, showed the overwhelming importance of coro nal flux tubes and their many possible ways of interaction. Subsequent and parallel theoretical studies and simulations, differentiating between the topology of interact ing fluxtubes, demonstrated that the mutual positioning and the way of interaction are important for the subsequent processes of energy release in flares and the many associated phenomena such as the expUlsion of jets and the emission of X -ray and microwave radiation. The new developments now enable researchers to understand and classify flares in a physically significant way. Various processes of accelera tion are active in and after flares on greatly varying timescales; these can now be distinguished and explained.
Filament Eruptions And The Impulsive Phase Of Solar Flares
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Author : S. W. Kahler
language : en
Publisher:
Release Date : 1988
Filament Eruptions And The Impulsive Phase Of Solar Flares written by S. W. Kahler and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1988 with categories.
We examine the observed development of filament eruptions in the impulsive phase of flares for evidence of how the eruption is driven. A possibility sometimes adopted as working hypothesis is that the filament eruption and accompanying coronal mass ejection are consequences of energy release in the flare impulsive phase; they are taken to be ejecta in the explosion resulting from the pressure pulse from plasma heating in the flare. Evidence against this view is from four flares in which, in H alpha movies, a filament eruption was observed during the flare impulsive phase defined by the E = approx. 30 keV hard X-ray emission observed with the U. of Calif. at Berkely detector on the ISEE 3 spacecraft. In each case we find that: 1) filament eruption began before onset of the impulsive phase; 2) eruptive motion is consistent with a smooth evolution through the impulsive phase, accelerating, but showing no new acceleration attributable to the impulsive phase; 3) brightening of the H alpha flare ribbons in the impulsive phase occurring in compact areas is much smaller than the overall span of the erupting filament; and 4) the observed projected speed is on the order of 100 km/s at the onset of the impulsive phase. These characteristics indicate that filament eruption is not driven by flare plasma pressure, but instead marks an eruption of magnetic field driven by a global MHD instability of the field configuration in the flare region. It appears that filament eruption and impulsive energy release are coordinated and driven by a common cause, the instability of the whole field configuration. A new mode of energy release, that of the impulsive phase, may be initiated when the eruptive motion surpasses some speed limit of order 100 km/s.
Eruptive Solar Flares
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Author :
language : en
Publisher:
Release Date : 1992
Eruptive Solar Flares written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1992 with categories.
A Study Of Physical Mechanisms For Filament Eruption And Coronal Mass Ejection Via Numerical Simulation
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Author : National Aeronautics and Space Administration (NASA)
language : en
Publisher: Createspace Independent Publishing Platform
Release Date : 2018-06-28
A Study Of Physical Mechanisms For Filament Eruption And Coronal Mass Ejection Via Numerical Simulation written by National Aeronautics and Space Administration (NASA) and has been published by Createspace Independent Publishing Platform this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-06-28 with categories.
It is well-known from both observation and theory that photospheric shear motion has played a key role in physical processes of the energy build-up and release for the solar flare. In order to further our understanding of the occurrence of solar flares it is necessary to investigate the triggering mechanism. One popular scenario for the onset of eruptive solar flares is that in response to photospheric shear motions the magnetic field evolves slowly through a series of magnetohydrodynamic-equilibria until a threshold is reached where magnetohydrodynamic (MHD) non-equilibrium sets in. Thus, a magnetic eruption occurs, causing the solar flare. To substantiate this claim we have employed our newly developed three-dimensional time-dependent MHD code with gravity to simulate the evolution of the coronal field. We use plasma beta = 0.1 to closely approximate the condition in the actual corona. Some preliminary results are presented. Wu, S. T. Unspecified Center NAGW-9...
Handbook Of Cosmic Hazards And Planetary Defense
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Author : Joseph N. Pelton
language : en
Publisher: Springer
Release Date : 2015-04-27
Handbook Of Cosmic Hazards And Planetary Defense written by Joseph N. Pelton and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015-04-27 with Technology & Engineering categories.
Covers in a comprehensive fashion all aspects of cosmic hazards and possible strategies for contending with these threats through a comprehensive planetary defense strategy. This handbook brings together in a single reference work a rich blend of information about the various types of cosmic threats that are posed to human civilization by asteroids, comets, bolides, meteors, solar flares and coronal mass ejections, cosmic radiation and other types of threats that are only recently beginning to be understood and studied, such as investigation of the “cracks” in the protective shield provided by the Van Allen belts and the geomagnetosphere, of matter-antimatter collisions, orbital debris and radiological or biological contamination. Some areas that are addressed involve areas about which there is a good deal of information that has been collected for many decades by multiple space missions run by many different space agencies, observatories and scientific researchers. Other areas involving research and studies that have only recently gotten underway are discussed by some of the world’s foremost experts in each of these areas, who provide up-to-date and scientifically verifiable information. Although much of the work in these various areas have been conducted by space agencies, an expanding range of work is also being carried out by observatories, by universities and other research centers, and even by private foundations and professional organizations. The purpose of this work is thus several-fold: to include the latest information and most systematic research from around the world in a single reference work; to note where there are significant gaps in knowledge where new research, spacecraft, observatories, or other initiatives are needed to fill in critical missing information; and to give the best possible information about preventative actions that might be taken against cosmic threats and identify various alternative strategies that are now under way or planned to cope with these various threats.
Eruptions On The Sun
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Author : Boris Filippov
language : en
Publisher: Springer Nature
Release Date :
Eruptions On The Sun written by Boris Filippov and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on with categories.
Variation Of Coronal Magnetic Field And Solar Flare Eruption
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Author : Han He
language : en
Publisher:
Release Date : 2020
Variation Of Coronal Magnetic Field And Solar Flare Eruption written by Han He and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with Electronic books categories.
Solar flares are prominent eruptive phenomenon happening in the solar atmosphere. Major flares usually come from solar active regions (ARs) where strong and concentrated bipolar magnetic field exists and manifests as dark sunspots in photosphere. The photospheric magnetic field acts as the bottom boundary of corona system and confines the magnetic structure of the corona. For complex ARs, the coronal magnetic field generally contains electric current around the magnetic polarity inversion lines, which corresponds to the nonpotential magnetic field and manifests as twisted field lines. The coronal magnetic field structure evolves as the response to the variations of the photospheric magnetic field. This coronal evolution can be quasi-steady and approximated by the force-free condition. In some situations, the variations of photospheric magnetic field may cause sudden changes of topological structure of coronal magnetic field at certain sites in the corona. The plasmas at these sites lost equilibrium and are ejected from their original positions. This process is accompanied with magnetic reconnection and leads to the release of magnetic energy in the corona. Part of the released magnetic energy is converted to the electromagnetic emission which manifests as sudden brightening across a broad range of electromagnetic wave spectrum, and hence the flare phenomenon is initiated.