Download or read book Hard X Ray Imaging of Solar Flares written by Michele Piana and published by Springer Nature. This book was released on 2022-01-01 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: The idea for this text emerged over several years as the authors participated in research projects related to analysis of data from NASA's RHESSI Small Explorer mission. The data produced over the operational lifetime of this mission inspired many investigations related to a specific science question: the when, where, and how of electron acceleration during solar flares in the stressed magnetic environment of the active Sun. A vital key to unlocking this science problem is the ability to produce high-quality images of hard X-rays produced by bremsstrahlung radiation from electrons accelerated during a solar flare. The only practical way to do this within the technological and budgetary limitations of the RHESSI era was to opt for indirect modalities in which imaging information is encoded as a set of two-dimensional spatial Fourier components. Radio astronomers had employed Fourier imaging for many years. However, differently than for radio astronomy, X-ray images produced by RHESSI had to be constructed from a very limited number of sparsely distributed and very noisy Fourier components. Further, Fourier imaging is hardly intuitive, and extensive validation of the methods was necessary to ensure that they produced images with sufficient accuracy and fidelity for scientific applications. This book summarizes the results of this development of imaging techniques specifically designed for this form of data. It covers a set of published works that span over two decades, during which various imaging methods were introduced, validated, and applied to observations. Also considering that a new Fourier-based telescope, STIX, is now entering its nominal phase on-board the ESA Solar Orbiter, it became more and more apparent to the authors that it would be a good idea to put together a compendium of these imaging methods and their applications. Hence the book you are now reading.

Download or read book The Impulsive Hard X rays from Solar Flares written by John Leach and published by . This book was released on 1984 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Great Microwave Bursts and Hard X Rays from Solar Flares written by Herbert J. Wiehl and published by . This book was released on 1983 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Early Detection of a Solar Flare written by Richard Frank Donnelly and published by . This book was released on 1968 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solar X-ray, extreme ultraviolet, H[alpha] and radio emission were studies to determine what solar radiation is best suited for an automatic flare alarm system aboard a satellite for the detection of the start of a solar flare. Although hard X-rays ([lambda] “1 Å), centimeter-wavelength solar radio bursts, and flashes at certain EUV wavelengths usually have faster rise times and peak earlier than soft X-rays in the 2-16 Å range, the data available to date show that on the average the start time of the 2-16 Å X-rays occurs earlier than the start times for these other types of data. The early start times and large percentage increase of 2-16 Å X-rays make this radiation the best suited for the automatic detection of solar flares for the present state of the art of solar radiation measurements.

Download or read book Contribution of X ray and Extreme Ultraviolet Radiation of Solar Flares to Sudden Frequency Deviations written by Richard Frank Donnelly and published by . This book was released on 1969 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: High time and intensity resolution satellite measurements of X-ray and extreme ultraviolet (EUV) radiation during solar flares are studied to determine the wavelength dependence of the flare radiation responsible for sudden frequency deviations (SFD). SFD's measure the flare-induced effects in the E and F1 regions of the ionosphere and are in effect like a broadband (1-1030 Å) detector for impulsive flare enhancements. He II 303.8 Å, O V 629.7 Å, H Ly [upsilon] 972.5 Å, C III 977.0 Å, and H Ly [alpha] 1215.7 Å were found to have essentially the same time dependence as the total ionizing radiation producing SFD's, except that they decay faster than the net 1-1030 Å radiation. Flare enhancements of Fe XV 284.1 Å, Fe XVI 335.3 Å, Si XII 499.3 Å. Mg X 625.3 Å, and Ne VIII 770.4 Å, which are normally coronal lines, appear to have a much slower time dependence than the radiation responsible for SFD's. X-rays in the 0.5-3 Å range are slightly slower than the radiation responsible for SFD's during the decay stage; 1-8 Å X-ray flares are slower, especially during the decay stages; and 8-20 Å flare radiation enhancements are slower throughout the entire SFD.

Download or read book Dynamic Evolution of the Source Volumes of Gradual and Impulsive Solar Flare Emissions written by and published by . This book was released on 1987 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Correlative Analysis of Hard and Soft X Ray Emissions in Solar Flares written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-16 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes research performed under the Phase 3 Compton Gamma-Ray Observatory (CGRO) Guest Investigator Program. The objective of this work is to study different mechanisms of solar flare heating by comparing their predictions with simultaneous hard and soft X-ray observations. The datasets used in this work consist of hard X-ray observations from the CGRO Burst and Transient Source Experiment (BATSE) and soft X-ray observations from the Bragg Crystal Spectrometer (BCS) and Soft X-ray telescope (SXT) on the Japanese Yohkoh spacecraft. Zarro, Dominic M. Goddard Space Flight Center NASA-CR-204530, NAS 1.26:204530, R97-257 NASA Order S-57783-F...

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 The Hard X Rays and Gamma Rays from Solar Flares written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-10-12 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radiation of energies from 10 KeV to greater than 10 MeV has been observed during solar flares, and is interpreted to be due to bremsstrahlung by relativistic electrons. A complete treatment of this problem requires solution of the kinetic equation for relativistic electrons and inclusion of synchrotron energy losses. Using the electron distributions obtained from numerical solutions of this equation the bremsstrahlung spectra in the impulsive x ray and gamma-ray regimes are calculated, and the variation of these spectral indices and directivities with energy and observation angle are described. The dependences of these characteristics of the radiation of changes in the solar atmospheric model, including the convergence of the magnetic field, the injected electron spectral index, and most importantly, in the anisotropy of the injected electrons and of the convergence of the magnetic field are also described. The model results are compared with stereoscopic observations of individual flares and the constraints that this data sets on the models are discussed. Mctiernan, James M. and Petrosian, Vahe Unspecified Center NSF ATM-83-20439; NSG-7092...

Download or read book X ray and Gamma ray Observations of Solar Flares written by Paul Thomas Feffer and published by . This book was released on 1996 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Solar Flare Physics written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-09-21 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Faint Coronal Hard X rays From Accelerated Electrons in Solar Flares written by Lindsay Erin Glesener and published by . This book was released on 2012 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solar flares are huge explosions on the Sun that release a tremendous amount of energy from the coronal magnetic field, up to 1033 ergs, in a short time (100--1000 seconds), with much of the energy going into accelerated electrons and ions. An efficient acceleration mechanism is needed, but the details of this mechanism remain relatively unknown. A fraction of this explosive energy reaches the Earth in the form of energetic particles, producing geomagnetic storms and posing dangers to spaceborne instruments, astronauts, and Earthbound power grids. There are thus practical reasons, as well as intellectual ones, for wishing to understand this extraordinary form of energy release. Through imaging spectroscopy of the hard X-ray (HXR) emission from solar flares, the behavior of flare-accelerated electrons can be studied. The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) spacecraft launched in 2002 with the goal of better understanding flare particle acceleration. Using rotation modulation collimators, RHESSI is able to cover a wide energy range (3 keV--17 MeV) with fine angular and energy resolutions. RHESSI's success in the last 10 years in investigating the relationship between energetic electrons and ions, the nature of faint sources in the corona, the energy distribution of flares, and several other topics have significantly advanced the understanding of flares. But along with the wealth of information revealed by RHESSI come some clear observational challenges. Very few, if any, RHESSI observations have come close to imaging the electron acceleration region itself. This is undoubtedly due to a lack of both sensitivity (HXRs from electron beams in the tenuous corona are faint) and dynamic range (HXR sources at chromospheric flare footpoints are much brighter and tend to obscure faint coronal sources). Greater sensitivity is also required to investigate the role that small flares in the quiet Sun could play in heating the corona. The Focusing Optics X-ray Solar Imager (FOXSI) is a developing project to address these observational difficulties. FOXSI is a sounding rocket payload developed under NASA's Low Cost Access to Space program. The project spearheads a shift to using direct imaging via focusing grazing-incidence HXR optics rather than the indirect Fourier techniques used by RHESSI and its predecessors. Such optics can attain higher sensitivity since photons are focused onto a small detector volume and have significantly better dynamic range than Fourier methods do. On November 2, 2012 the FOXSI rocket payload was flown for a 6-minute observation and successfully imaged a solar flare, providing the first focused HXR spectroscopic images of the Sun above 5 keV. The motivation, construction, testing, and flight of FOXSI will be described in this text, along with case studies on the use of FOXSI to analyze unique coronal HXR sources from two solar flares.

Download or read book Recent Advances in the Understanding of Solar Flares written by S.R. Kane and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 451 pages. Available in PDF, EPUB and Kindle. Book excerpt: These Proceedings result from the papers and discussions of the U.S.-Japan Seminar "Recent Advances in the Understanding of Solar Flares" held in Tokyo October 5-8, 1982. The meeting was sponsored jointly by the Japan Society for the Promotion of Science and the u.S. National Science Foundation. The principal aim of the meeting was to obtain the most up-to-date physical picture of solar flares by bringing together results from the recent observations by the Solar Maximum Mission (SMM) and HINOTORI satellites, together with other satellite data and ground-based data at both optical and radio wavelengths. These data cover the recent maximum of the solar activity cycle. The SMM and HINOTORI introduced a new dimension in flare observations by carrying out the first hard X-ray imaging observations, and the organizers especially felt that an intense discussion of the significance of these results in the context of flare theories would be important. Starting with an introductory presentation of the characteristics of the instruments on board the satellites, the sessions of the first day and the beginning of the second dealt mainly with energy transport in flares and with .the formation process of the hot plasma which is .

Download or read book Solar Flares and Collisions between Current Carrying Loops written by Jun-Ichi Sakai and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Solar Gamma X and EUV Radiation written by S.R. Kane and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of IAU Symposium No. 68 held in Buenos Aires, Argentina, 11-14 June 1974, organized by the IAU in co-operation with COSPAR

Download or read book The Complete Hard X Ray Burst Spectrometer Event List 1980 1989 written by B. R. Dennis and published by . This book was released on 1991 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive reference for all Hard X ray bursts detected with the Hard X Ray Burst Spectrometer on the Solar Maximum Mission from the time of launch on Feb. 14, 1980 to the end of the mission in Dec. 1989. Includes the start time, peak time, duration, and peak rate of each event.