Download or read book Thermal and Nonthermal Radiation Signatures in Solar Flares written by Sarah H. Matthews and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thermal and Nonthermal Radiation Signatures in Solar Flares written by Sarah A. Matthews and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Thermal nonthermal Approach to Solar Flares written by Stephen G. Benka and published by . This book was released on 1991 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Thermal Nonthermal Approach to Solar Flares written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-17 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: An approach for modeling solar flare high-energy emissions is developed in which both thermal and nonthermal particles coexist and contribute to the radiation. The thermal/nonthermal distribution function is interpreted physically by postulating the existence of DC sheets in the flare region. The currents then provide both primary plasma heating through Joule dissipation, and runaway electron acceleration. The physics of runaway acceleration is discussed. Several methods are presented for obtaining approximations to the thermal/nonthermal distribution function, both within the current sheets and outside of them. Theoretical hard x ray spectra are calculated, allowing for thermal bremsstrahlung from the heated plasma electrons impinging on the chromosphere. A simple model for hard x ray images of two-ribbon flares is presented. Theoretical microwave gyrosynchrotron spectra are calculated and analyzed, uncovering important new effects caused by the interplay of thermal and nonthermal particles. The theoretical spectra are compared with observed high resolution spectra of solar flares, and excellent agreement is found, in both hard x rays and microwaves. The future detailed application of this approach to solar flares is discussed, as are possible refinements to this theory. Benka, Stephen G. Goddard Space Flight Center CURRENT SHEETS; ELECTRON ACCELERATION; NONTHERMAL RADIATION; PLASMA HEATING; SOLAR FLARES; SOLAR RADIATION; SOLAR SPECTRA; SPACE PLASMAS; THERMAL RADIATION; BREMSSTRAHLUNG; CHROMOSPHERE; DISSIPATION; IMPINGEMENT; MICROWAVE SPECTRA; MICROWAVES; PLASMA CURRENTS; X RAY SPECTRA; X RAYS...
Download or read book Kappa Distributions written by Marian Lazar and published by Springer Nature. This book was released on 2021-12-02 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents recent results on the modelling of space plasmas with Kappa distributions and their interpretation. Hot and dilute space plasmas most often do not reach thermal equilibrium, their dynamics being essentially conditioned by the kinetic effects of plasma particles, i.e., electrons, protons, and heavier ions. Deviations from thermal equilibrium shown by these plasma particles are often described by Kappa distributions. Although well-known, these distributions are still controversial in achieving a statistical characterization and a physical interpretation of non-equilibrium plasmas. The results of the Kappa modelling presented here mark a significant progress with respect to all these aspects and open perspectives to understanding the high-resolution data collected by the new generation of telescopes and spacecraft missions. The book is directed to the large community of plasma astrophysics, including graduate students and specialists from associated disciplines, given the palette of the proposed topics reaching from applications to the solar atmosphere and the solar wind, via linear and quasilinear modelling of multi-species plasmas and waves within, to the fundamental physics of nonequilibrium plasmas.
Download or read book Studying the Thermal Non Thermal Crossover in Solar Flares written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-11 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes work performed under contract NAS5-32584 for Phase 3 of the Compton Gamma Ray Observatory (CGRO) from 1 November 1993 through 1 November 1994. We have made spectral observations of the hard x-ray and gamma-ray bremsstrahlung emissions from solar flares using the Burst and Transit Source Experiment (BASTE) on CGRO. These measurements of their spectrum and time profile provided valuable information on the fundamental flare processes of energy release, particle acceleration, and energy transport. Our scientific objective was to study both the thermal and non-thermal sources of solar flare hard x-ray and gamma-ray emission. Schwartz, R. A. Unspecified Center NAS5-32584...
Download or read book Particle kinematics in solar flares observations and theory written by Marina Battaglia and published by Cuvillier Verlag. This book was released on 2009-02-05 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is devoted to the study of particle acceleration and propagation processes in solar flares. Solar flares are amongst the most powerful and energetic activity phenomena our Sun exhibits. They release energy of the order of 1032 erg in seconds to minutes. In the process, electrons and protons are accelerated to relativistic energies, making flares very efficient particle accelerators. The most compelling observational signatures of flares can be found in X-rays and extreme ultra-violet wavelengths. Due to atmospheric absorption, those wavelengths can only be studied from space. Since the beginning of the space age, countless flares have been observed by satellites. The present work is largely based on observations by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI), an X-ray satellite which has been observing the Sun since February 2002. It is a NASA mission with substantial Swiss hardware and software contribution. Using RHESSI observations of flares of different intensity, a deeper understanding of the particle transport and energy transport processes in flare loops, as well as the acceleration site and acceleration mechanism is sought. The time evolution of images and spectra is studied along with the quantitative relations between X-ray sources observed in the corona (coronal sources) and from the chromosphere (footpoints). The spectral relations found between coronal sources and footpoints are compared to the so-called ``intermediate thin-thick target model'', which was based on observations by the satellite Yohkoh. We show that the spectral relations between coronal sources and footpoints observed with RHESSI cannot be explained by the intermediate thin-thick target model. In a next step, return currents in the flare loop were considered. With this extension to the existing model, the spectra of the coronal source and the footpoints, as well as the relations between them can be explained, indicating the importance of return currents in flare loops. In a second part, observations of so-called ``pre-flares'' are presented. This earliest phase of a flare cannot be explained by the standard flare model of chromospheric evaporation which involves energy transport and deposition in the chromosphere by beams of accelerated electrons. In pre-flares, an increase in density and emission measure is observed, indicating that chromospheric evaporation is occurring. However, no observational signatures of fast electrons are found. We show that if energy is transported by means of thermal conduction instead of an electron beam, the observations can explained.
Download or read book Energetics and Dynamics of Simple Impulsive Solar Flares written by and published by . This book was released on 1987 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energetics and Dynamics of Simple Impulsive Solar Flares written by R. Starr and published by . This book was released on 1987 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Simulations of Radiation and Heating from Non thermal Electrons in Solar Flares written by Jennifer A. Pollock and published by . This book was released on 2008 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Particle Acceleration and Kinematics in Solar Flares written by Markus Aschwanden and published by Springer Science & Business Media. This book was released on 2002-09-30 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last decade we entered a new exploration phase of solar flare physics, equipped with powerful spacecraft such as Yohkoh, SoHO, and TRACE that pro vide us detail-rich and high-resolution images of solar flares in soft X-rays, hard X -rays, and extreme-ultraviolet wavelengths. Moreover, the large-area and high sensitivity detectors on the Compton GRO spacecraft recorded an unprecedented number of high-energy photons from solar flares that surpasses all detected high energy sources taken together from the rest of the universe, for which CGRO was mainly designed to explore. However, morphological descriptions of these beau tiful pictures and statistical catalogs of these huge archives of solar data would not convey us much understanding of the underlying physics, if we would not set out to quantify physical parameters from these data and would not subject these measurements to theoretical models. Historically, there has always been an unsatisfactory gap between traditional astronomy that dutifully describes the mor phology of observations, and the newer approach of astrophysics, which starts with physical concepts from first principles and analyzes astronomical data with the goal to confirm or disprove theoretical models. In this review we attempt to bridge this yawning gap and aim to present the recent developments in solar flare high-energy physics from a physical point of view, structuring the observations and analysis results according to physical processes, such as particle acceleration, propagation, energy loss, kinematics, and radiation signatures.
Download or read book Solar Flares written by Zdenek Svestka and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the first part of the originally planned publication by Z. Svestka and L. D. de Feiter 'Solar High Energy Photon and Particle Emission'. The second part, with the original title, was to be published by de Feiter in about one year from now. However, to the deep sorrow of all of us, Dr de Feiter died suddenly and unexpectedly when the present book was in print. Thus, unfortunately, de Feiter's second part may not appear. Due to the fact that the originally planned publication was divided into two parts, the present book is mainly descriptive and concerned with the flare morphology. It was expected that theoretical interpretations would be extensively developed in the second part, prepared by de Feiter. In particular, this refers to the theoretical back grounds of radio emissions, particle acceleration and particle propagation in space. Only in Chapter II, concerning the 'low-temperature' flare, do we go deeper into the theoretical interpretations, anticipating that de Feiter would have been concerned mainly with the 'high-energy' physics. Still, the book includes discussions on all important aspects of flares and thus can present the reader with a complete picture of the complex flare phenomenon. It is clear that many observed data on flares can be interpreted in different ways.
Download or read book Solar Flare Loops Observations and Interpretations written by Guangli Huang and published by Springer. This book was released on 2018-01-31 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides results of analysis of typical solar events, statistical analysis, the diagnostics of energetic electrons and magnetic field, as well as the global behavior of solar flaring loops such as their contraction and expansion. It pays particular attention to analyzing solar flare loops with microwave, hard X-ray, optical and EUV emissions, as well as the theories of their radiation, and electron acceleration/transport. The results concerning influence of the pitch-angle anisotropy of non-thermal electrons on their microwave and hard X-ray emissions, new spectral behaviors in X-ray and microwave bands, and results related to the contraction of flaring loops, are widely discussed in the literature of solar physics. The book is useful for graduate students and researchers in solar and space physics.
Download or read book Physical Processes in Solar Flares written by B.V. Somov and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solar flares are very complex electromagnetic phenomena of a cataclysmic nature. Particles are accelerated to very high velocities and a variety of physical processes happen inside and outside flares. These processes can be studied by a large number of techniques from Earth and from space. The aim is to discover the physics behind solar flares. This goal is complicated because information about the flare mechanism can be obtained only in an indirect way by studying the secondary effects. This book provides three stages in the solution of the solar flare problem. Chapter one describes the connection between observational data and theoretical concepts, where it is stressed that next to investigating flares, the related non-stationary large-scale phenomena must be studied as well. The second chapter deals with secondary physical processes, in particular the study of high-temperature plasma dynamics during impulsive heating. The last chapter presents a model built on the knowledge of the two previous chapters and it constructs a theory of non-neutral turbulent current sheets. The author believes that this model will help to solve the problem of solar flares. For solar physicists, plasma physicists, high-energy particle physicists.
Download or read book The Physics of Solar Flares written by Einar Tandberg-Hanssen and published by Cambridge University Press. This book was released on 1988-11-17 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors explore solar flares by applying physics and theoretical investigations.
Download or read book Particle Acceleration and Trapping in Solar Flares written by G. Trottet and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: These are the Proceedings of the Second CESRA Workshop on Particle Acceleration and Trapping in Solar Flares. The Workshop was held on June 23-26,1986, at the city hall of Aubigny-sur-Nere (France), near Bourges and near the Nan
Download or read book MAX 91 written by and published by . This book was released on 1988 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
