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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

by Peter A. Sturrock

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  • 4 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

    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.


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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, as 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 is 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, as 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 usually 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 spatial and temporal evolution of photospheric magnetic fields in the active region NOAA that produced eight 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.