Last edited by Mooguhn
Monday, April 27, 2020 | History

3 edition of Coronal magnetic fields produced by photospheric shear found in the catalog.

Coronal magnetic fields produced by photospheric shear

Peter A. Sturrock

Coronal magnetic fields produced by photospheric shear

  • 107 Want to read
  • 23 Currently reading

Published by Center for Space Science and Astrophysics, Stanford University, National Aeronautics and Space Administration, National Technical Information Service, distributor in Stanford, Calif, [Washington, DC, Springfield, Va .
Written in English

    Subjects:
  • Solar activity.

  • Edition Notes

    StatementP.A. Sturrock, W-H. Yang.
    SeriesNASA contractor report -- NASA CR-181514.
    ContributionsYang, W-H., United States. National Aeronautics and Space Administration.
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL15399228M

    Full text of "Study of the Source Regions of Coronal Mass Ejections Using Yohkoh SXT Data" See other formats NASA-CR / HNAL REPORT for: NASA GRANT NAGW Title: STUDY OF THE SOURCE REGIONS OF CORONAL MASS EJECTIONS USING YOHKOH SXT DATA By: David F. Webb, Principal Investigator Institute for Scientific Research Boston College St. Clements Hall . 2. General properties of filament magnetic fields The magnetic fie lfds ilaminents are nealry horizon taalndgenera llexhy ib ia het lical structure inside an arcade of coronal loops (Athay et al. , Rust & Kumar ). Fig. 1 is a sketch of an idealized twisted-field filament and its magnetic arcade. The. The relatively high magnetic field strength of G used for the normalization in Equations and is thought to be realistic above plages with high filling factor of photospheric faculae and the typical kG source fields (Spruit ; Schrijver & Zwaan ). A shear field of 50 G also appears to be a rather high : Gerhard Haerendel. It is stretched thin and opened wide in coronal holes, with their open magnetic fields and fast, tenuous solar wind, but the chromosphere is compressed below magnetically closed regions associated with the gusty, slow dense solar wind outflow (Fig )/5.


Share this book
You might also like
Beyond Bad

Beyond Bad

Americas drug strategy

Americas drug strategy

Greatness in music

Greatness in music

Relation between physical and magnetic hardness of certain carbon steels

Relation between physical and magnetic hardness of certain carbon steels

Catalogue of printed books: Bible.

Catalogue of printed books: Bible.

encyclopaedia of shells

encyclopaedia of shells

Colorado strategy for homeland security.

Colorado strategy for homeland security.

An answer to the insinuations and suggestions of the commissioners, for receiving the duties on glass-wares

An answer to the insinuations and suggestions of the commissioners, for receiving the duties on glass-wares

All Alone in the World

All Alone in the World

Hill forts of the Stour Valley

Hill forts of the Stour Valley

Coronal magnetic fields produced by photospheric shear by Peter A. Sturrock Download PDF EPUB FB2

The magneto-frictional method for computing force-free fields examines the evolution of the magnetic field of a line dipole, when there is relative shearing motion between the two polarities. The energy of the sheared field can be arbitrarily large compared with the potential field.

It is possible to fit the magnetic energy, Coronal magnetic fields produced by photospheric shear book a function of shear amplitude, by a simple functional by: Coronal magnetic fields produced by photospheric shear Article (PDF Available) in The Astrophysical Journal (1) January with 24 Reads How we measure 'reads'.

The magneto-frictional method is used for computing force free fields to examine the evolution of the magnetic field of a line dipole, when there Coronal magnetic fields produced by photospheric shear book relative shearing motion between the two polarities.

It found that the energy of the sheared field can be arbitrarily large compared with the potential field. It is also found that it is possible to fit the magnetic energy, as a function of shear Author: P.

Sturrock, W.-H. Yang. The solar magnetic field controls the dynamics and topology of all coronal phenomena. Heated plasma flows along magnetic field lines and energetic particles can only propagate along magnetic field lines.

Coronal loops are nothing other than conduits filled with heated plasma, shaped by the geometry of the coronal magnetic field, where cross-field diffusion is strongly inhibited.

These currents are believed to emerge from the convection zone (e.g., Leka et al, ) or be produced by photospheric flows that shear and twist the coronal magnetic field (e.g., Klimchuk and.

Force-free magnetic fields - The magneto-frictional method. and associated photospheric velocity shear within a flare-productive active region Coronal magnetic fields produced by. In this study, 3D coronal magnetic field was extrapolated based on the vercormagnetogram data on Dec, from Hinode/SP data under the Nonlinear Force-Free (NLFF) approximation and the Author: Han He.

Variation of coronal magnetic field and solar flare eruption Quasi-steady evolution of the corona Because the photospheric magnetic field confines the magnetic structure in corona, along with the evolution of the photospheric magnetic field, the coronal magnetic field also evolves accordingly as the response to the variations in : Han He.

The structure and dynamics of the solar corona is dominated by the magnetic field. In most areas in the corona magnetic forces are so dominant that all non-magnetic forces like plasma pressure gradient and gravity can be neglected in the lowest order.

This model assumption is called the force-free field assumption, as the Lorentz force vanishes. This can be obtained by either vanishing Cited by: Magnetic loops with constant thickness, Coronal magnetic fields produced by photospheric shear book an extreme case in the dipole nonlinear force-free fields, can be reached asymptotically when the magnetic shear increases.

Equation (5) means that, in the force‐free magnetic field, α is a constant along each field line. If α takes the same value for all the field lines, the magnetic field is regraded as a linear force‐free field (LFFF).

But in general condition, the values of α are Coronal magnetic fields produced by photospheric shear book different for different field lines.

This general case is called nonlinear force‐free field (NLFFF) or nonconstant Cited by: Magnetic fields in the Sun’s outer atmosphere—the corona—control both solar-wind acceleration and the dynamics of solar eruptions.

We present the first clear observational evidence of coronal magnetic nulls in off-limb linearly polarized observations of pseudostreamers, taken by the Coronal. Abstract. To better understand a preferred magnetic field configuration and its evolution during coronal mass ejection (CME) events, we investigated the Coronal magnetic fields produced by photospheric shear book and temporal evolution of photospheric magnetic fields in the active region NOAA that produced Coronal magnetic fields produced by photospheric shear book flare-associated CMEs during the time period of November Solar Force-free Magnetic Fields 5 1 Introduction The magnetic activity of the Sun has a high impact on Earth.

As illustrated in Figure1, large coronal eruptions like flares and coronal mass ejections can influence the Earth’s magnetosphere where they trigger magnetic storms and cause aurorae.

These coronal eruptions have also harm-Cited by: Two profoundly different views of the coronal magnetic field have emerged. In quasi-steady models, the predominant source of open magnetic field is in coronal holes. In contrast, in the interchange model, the open magnetic flux is conserved, and the coronal magnetic field can only respond to the photospheric evolution via interchange reconnection.

@article{osti_, title = {Are Complex Magnetic Field Structures Responsible for the Confined X-class Flares in Super Active Region ?}, author = {Zhang, Jun and Li, Ting and Chen, Huadong}, abstractNote = {From October 19 to 27, six X-class flares occurred in super active region (AR) They were all confined flares and were not followed by coronal mass ejections.

the nonpotentiality of coronae of solar active regions, the dynamics of the surface magnetic field, and the potential for large flares. The solar corona is the most external, rarefied and hottest part of the Sun’s atmosphere, which is formed by a plasma at an average temperature of the order of or larger than T ∼ 10 6 K.

It is permeated by a strongly inhomogeneous magnetic field which is generated by the dynamo mechanism [1,2,3,4,5,6,7] operating in the solar convection coronal magnetic structures, coronal loops.

The Sun is the star at the center of the Solar is a nearly perfect sphere of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process.

It is by far the most important source of energy for life on diameter is about million kilometers (, miles), or times that of Earth, and its mass is abouttimes that of distance from Earth: 1 au ≈ ×10⁸ km, 8 min. The dispersal of the active-region strong fields over ever-larger photospheric regions leaves behind coronal remnant fields that remain highly structured well after the progenitor sunspots have decayed and after the active-region fields have fallen into the background photospheric strength of ≈10 G.

Field strength thus increases with height Cited by: 1. X-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical objects. X-radiation is absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and satellites.X-ray astronomy is the space science related to a type of space telescope that can see.

A uniform set of computed large-scale coronal fields derived from photospheric field observations now exists for the interval to the present. Using this data base we can begin to compare Solar Cycle 21 with Solar Cycle The character of the field and its evolution are the. FIGURE Left: White-light image of the solar corona out to 4 solar radii during the solar eclipse of J Right: Predictive Science, Inc., prediction of the magnetic field during the Jeclipse, using observations of photospheric magnetic field and numerical simulation of magnetized fluid.

SOURCE: Left: Courtesy of M. Druckmüller, M. Dietzel, S. Habbal, and V. Rušin. Chapters cover the generation of the Sun's magnetic field by dynamo action, magnetoconvection and the nature of photospheric flux tubes such as sunspots, the heating of the outer atmosphere by waves or reconnection, the structure of prominences, the nature of eruptive instability and magnetic reconnection in solar flares and coronal mass.

The Sun, our nearest star, is the gravity center and ultimate energy source for many processes in our solar system. We give a physical description of the Sun, from inward to outward, starting with the solar interior, and continuing to the photospheric surface, the chromosphere, and to the corona, which displays eruptive phenomena such as flares, and coronal mass ejections, a rich realm of high Cited by: 1.

We conclude that a large-aperture solar telescope is an essential part of a program that studies the Sun and its processes as a complex, coupled physical system. High angular resolution is required to study the small scale end of the broad spectrum of phenomena that need to be understood.

Coronal holes are associated with rapidly expanding open magnetic fields and the acceleration of the high-speed solar wind. This paper reviews measurements of the plasma properties in coronal holes and how these measurements are used to reveal details about the physical processes that heat the solar corona and accelerate the solar wind.

Magnetohydrodynamics in solar coronal and laboratory plasmas: A comparative study. up, and their relevance to the two systems discussed. It is shown that in both cases the resistivity is small, and the magnetic field is strong, so that similar physical behaviour should be expected.

and relaxation of magnetic fields and helicity Cited by:   Coronal holes are the darkest and least active regions of the Sun, as observed both on the solar disk and above the solar limb. Coronal holes are associated with rapidly expanding open magnetic fields and the acceleration of the high-speed solar wind.

This paper reviews measurements of the plasma properties in coronal holes and how these measurements are used to reveal details about Author: Steven R. Cranmer.

A coronal cloud is a cloud, or cloud-like, natural astronomical entity, composed of plasmas and usually associated with a star or other astronomical object where the temperature is such that X-rays are emitted.

While small coronal clouds are above the photosphere of many different visual spectral type stars, others occupy parts of the interstellar medium (ISM), extending sometimes millions of.

The phenomenon of the solar modulation of cosmic rays is the result of the solar wind and its magnetic field inhibiting the interstellar cosmic rays from entering the inner solar system. This invited memoire describes my fortunate life, which has been enriched by meeting many wonderful people.

The story starts at home and university, and continues with accounts of St Andrews and trips to the USA, together with musings on the book Solar MHD. The nature and results of collaborations with key people from abroad and with students is mentioned at by: 1. An "antidynamo theorem is one of several results that restrict the type of magnetic fields that may be produced by dynamo action."No "axisymmetric magnetic field can be maintained through a self-sustaining dynamo action by an axially symmetric current." A "dipole, an axisymmetric magnetic field.

This paper outlines the current understanding of solar flares, mainly focused on magnetohydrodynamic (MHD) processes responsible for producing a flare. Observations show that flares are one of the most explosive phenomena in the atmosphere of the Sun, releasing a huge amount of energy up to about erg on the timescale of hours.

Flares involve the heating of plasma, mass Cited by: Information on the highest energies of particles produced during solar flares, measured in gamma-ray wavelengths with photon energies of E ≳ keV, has been obtained by very few instruments on a.

1 Introduction. Coronal mass ejections (CMEs) are large clouds of plasma and magnetic flux expelled from the Sun into the heliosphere. If directed toward Earth, they can cause significant space weather effects upon impact with the near‐Earth by: represents red shifts or downflows.

The blue regions are inside a coronal hole, or open magnetic field region, where the high-speed solar wind is accelerated. Superposed are the edges of ‘honeycomb-shaped’ patterns of magnetic fields at the surface of the Sun (from Hassler et al.) the river, they have measured the acceleration.

Title: Photospheric Magnetic Activities to Trigger Micro-Flares observed with the Hinode SOT and XRT. Abstract: For understanding the coronal heating, it is important to reveal the coupling between photospheric magnetic activities and coronal transient events.

Micro-flares are a good target to study the coupling, because they are smaller and. Dynamic and Topological Features of Photospheric and Coronal Activities Produced by Flux Emergence in the Sun 17 A&A M Murray, M.

J.; Hood, A. W.; Moreno-Insertis, F. While sunspots are very important to understand the global solar magnetic field dynamo, as well as the caused large scale-solar activity, and hence the space weather and its influence on Earth, small-scale solar magnetic fields can teach us about important magneto-plasma processes such as MHD wave generation and propagatin.

Coronal holes are the darkest and least active regions of the Pdf, as observed both on the solar disk and above the solar limb. Coronal holes are associated with rapidly expanding open magnetic fields and the acceleration of the high-speed solar wind.You can write a book review and share your experiences.

Other readers will always download pdf interested in your opinion of the books you've read. Whether you've loved the book or not, if you give your honest and detailed thoughts then people will find new books that are right for them.

Connection between photospheric magnetic fields and coronal structure/dynamics Shimojo,M., Hara,H., and Kano,R.ebook Observations of Coronal Structure and Dynamics", Proc.

Yohkoh 10th Anniversary Meeting, held in Kona, Hawaii, USA, JanCOSPAR Colloquia Series, Vol. 13, (eds. Martens,P.C.H. and Cauffman,D.