Polar magnetic fields of the Sun: 1960?1971

AbstractRecent dedicated HINODE polar region campaign revealed the presence of concentrated kilogauss patches of magnetic field in the polar regions of Sun which are also shown to be correlated with facular bright points at the photospheric level. In this work, we demonstrate that this spatial intermittency of the magnetic field persists even up to the chromospheric heights. Polar network bright points are the ones which are present in the polar regions of the Sun (above 70° latitudes). We use special HINODE campaigns devoted to observe polar regions of the Sun to study the polar network bright points during the phase of last extended solar minimum. We are able to find a considerable association between the polar network bright points and magnetic field concentrations which led us to conclude that these bright points can serve as a good proxy for polar magnetic fields where the direct and regular measurements of polar magnetic fields are not available (before 1970).

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Polar magnetic field reversals on the Sun

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307010551 ◽

2006 ◽

Vol 2 (14) ◽

pp. 273-274 ◽

Cited By ~ 2

Author(s):

Elena E. Benevolenskaya

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Polar Region ◽

Small Scale ◽

The Sun ◽

Field Reversal ◽

Polar Magnetic Field ◽

The North ◽

Magnetic Elements ◽

Polar Magnetic Fields

AbstractThe polar magnetic fields on the Sun have been an attractive subject for solar researches since Babcock measured them in solar cycle 19. One of the remarkable features of the polar magnetic fields is their reversal during the maxima of 11-year sunspot cycles. I have present results of the investigations of the polar magnetic field using SOHO-mdi data. It is found, that the polar magnetic field reversal is detected with mdi data for polar region within 78°–88°. The North Pole has changed polarity in CR1975 (April 2001). The South reversed later in CR1980 (September 2001). The total unsigned magnetic flux does not show the dramatic decreasing during the polar reversals due to omnipresent bi-polar small-scale magnetic elements. The observational and theoretical aspects of the polar magnetic field reversals are discussed.

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Phase reversals in the polar magnetic fields of the sun and in the annual and semiannual variations in cosmic ray intensity

The Astrophysical Journal ◽

10.1086/155954 ◽

1978 ◽

Vol 220 ◽

pp. 712 ◽

Cited By ~ 21

Author(s):

E. Antonucci ◽

D. Marocchi ◽

G. E. Perona

Keyword(s):

Magnetic Fields ◽

Cosmic Ray ◽

The Sun ◽

Cosmic Ray Intensity ◽

Polar Magnetic Fields

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Dynamics of Phase Synchronization between Solar Polar Magnetic Fields Assessed with Van Der Pol and Kuramoto Models

Entropy ◽

10.3390/e22090945 ◽

2020 ◽

Vol 22 (9) ◽

pp. 945

Author(s):

Anton Savostianov ◽

Alexander Shapoval ◽

Mikhail Shnirman

Keyword(s):

Time Series ◽

Magnetic Fields ◽

Phase Difference ◽

Coupled Oscillators ◽

Ad Hoc ◽

Phase Synchronization ◽

Solar Dynamo ◽

The Sun ◽

Van Der Pol ◽

Polar Magnetic Fields

We establish the similarity in two model-based reconstructions of the coupling between the polar magnetic fields of the Sun represented by the solar faculae time series. The reconstructions are inferred from the pair of the coupled oscillators modelled with the Van der Pol and Kuramoto equations. They are associated with the substantial simplification of solar dynamo models and, respectively, a simple ad hoc model reproducing the phenomenon of synchronization. While the polar fields are synchronized, both of the reconstruction procedures restore couplings, which attain moderate values and follow each other rather accurately as the functions of time. We also estimate the evolution of the phase difference between the polar fields and claim that they tend to move apart more quickly than approach each other.

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Solar corona during the total solar eclipse of August 1, 2008 and polar magnetic fields of the Sun

Bulletin of Taras Shevchenko National University of Kyiv Astronomy ◽

10.17721/btsnua.2015.52.23-27 ◽

2015 ◽

Vol 52 (1) ◽

pp. 23-27

Author(s):

M. Pishkalo ◽

Keyword(s):

Magnetic Fields ◽

Solar Corona ◽

Solar Eclipse ◽

Total Solar Eclipse ◽

The Sun ◽

Polar Magnetic Fields

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Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening

International Astronomical Union Colloquium ◽

10.1017/s0252921100064630 ◽

2000 ◽

Vol 179 ◽

pp. 263-264

Author(s):

K. Sundara Raman ◽

K. B. Ramesh ◽

R. Selvendran ◽

P. S. M. Aleem ◽

K. M. Hiremath

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Magnetic Flux ◽

Ultra Violet ◽

Active Regions ◽

Morphological Properties ◽

Energy Storage And Conversion ◽

The Sun ◽

X Rays ◽

The Magnetic Field

Extended AbstractWe have examined the morphological properties of a sigmoid associated with an SXR (soft X-ray) flare. The sigmoid is cospatial with the EUV (extreme ultra violet) images and in the optical part lies along an S-shaped Hαfilament. The photoheliogram shows flux emergence within an existingδtype sunspot which has caused the rotation of the umbrae giving rise to the sigmoidal brightening.It is now widely accepted that flares derive their energy from the magnetic fields of the active regions and coronal levels are considered to be the flare sites. But still a satisfactory understanding of the flare processes has not been achieved because of the difficulties encountered to predict and estimate the probability of flare eruptions. The convection flows and vortices below the photosphere transport and concentrate magnetic field, which subsequently appear as active regions in the photosphere (Rust & Kumar 1994 and the references therein). Successive emergence of magnetic flux, twist the field, creating flare productive magnetic shear and has been studied by many authors (Sundara Ramanet al.1998 and the references therein). Hence, it is considered that the flare is powered by the energy stored in the twisted magnetic flux tubes (Kurokawa 1996 and the references therein). Rust & Kumar (1996) named the S-shaped bright coronal loops that appear in soft X-rays as ‘Sigmoids’ and concluded that this S-shaped distortion is due to the twist developed in the magnetic field lines. These transient sigmoidal features tell a great deal about unstable coronal magnetic fields, as these regions are more likely to be eruptive (Canfieldet al.1999). As the magnetic fields of the active regions are deep rooted in the Sun, the twist developed in the subphotospheric flux tube penetrates the photosphere and extends in to the corona. Thus, it is essentially favourable for the subphotospheric twist to unwind the twist and transmit it through the photosphere to the corona. Therefore, it becomes essential to make complete observational descriptions of a flare from the magnetic field changes that are taking place in different atmospheric levels of the Sun, to pin down the energy storage and conversion process that trigger the flare phenomena.

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Solar Filaments as Tracers of Subsurface Processes

International Astronomical Union Colloquium ◽

10.1017/s0252921100064459 ◽

2000 ◽

Vol 179 ◽

pp. 177-183

Author(s):

D. M. Rust

Keyword(s):

Magnetic Fields ◽

Magnetic Flux ◽

Coronal Mass Ejections ◽

Interplanetary Space ◽

Intermediate Stage ◽

Coronal Plasma ◽

Magnetic Helicity ◽

The Sun ◽

New Paradigm ◽

Solar Filaments

AbstractSolar filaments are discussed in terms of two contrasting paradigms. The standard paradigm is that filaments are formed by condensation of coronal plasma into magnetic fields that are twisted or dimpled as a consequence of motions of the fields’ sources in the photosphere. According to a new paradigm, filaments form in rising, twisted flux ropes and are a necessary intermediate stage in the transfer to interplanetary space of dynamo-generated magnetic flux. It is argued that the accumulation of magnetic helicity in filaments and their coronal surroundings leads to filament eruptions and coronal mass ejections. These ejections relieve the Sun of the flux generated by the dynamo and make way for the flux of the next cycle.

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The Interpretation of Line Profiles

International Astronomical Union Colloquium ◽

10.1017/s0252921100053318 ◽

1977 ◽

Vol 36 ◽

pp. 191-215

Author(s):

G.B. Rybicki

Keyword(s):

Magnetic Fields ◽

Atomic Physics ◽

Velocity Fields ◽

Spectral Lines ◽

Inhomogeneous Structure ◽

The Sun ◽

Line Profiles ◽

Physical Phenomena

Observations of the shapes and intensities of spectral lines provide a bounty of information about the outer layers of the sun. In order to utilize this information, however, one is faced with a seemingly monumental task. The sun’s chromosphere and corona are extremely complex, and the underlying physical phenomena are far from being understood. Velocity fields, magnetic fields, Inhomogeneous structure, hydromagnetic phenomena – these are some of the complications that must be faced. Other uncertainties involve the atomic physics upon which all of the deductions depend.

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Endless skies and open seas – how birds and fish navigate

Neuroforum ◽

10.1515/nf-2021-0009 ◽

2021 ◽

Vol 0 (0) ◽

Cited By ~ 1

Author(s):

Lisa Spiecker ◽

Bo Leberecht ◽

Corinna Langebrake ◽

Malien Laurien ◽

Shambhavi Rajendra Apte ◽

...

Keyword(s):

Mechanical Properties ◽

Magnetic Fields ◽

Home Range ◽

Environmental Conditions ◽

Geomagnetic Field ◽

Visual Cues ◽

Quantum Mechanical ◽

The Sun ◽

Seasonal Migrations ◽

Research Questions

Abstract Every year, billions of animals leave their home range and start seasonal migrations in order to find more favorable resources and to escape harsh environmental conditions. These round trips often span thousands of kilometers. To successfully navigate along their route, animals rely on various external references. While landmarks and celestial cues like stars or the sun are easy to imagine as guidance on these journeys, using the geomagnetic field for orientation is more elusive. The geomagnetic field is an omnipresent cue, which can be sensed and relied upon by many animals, even when visual cues are sparse. How magnetic fields can be perceived seems to vary between birds and fish. While birds seem to use a mechanism based on the quantum mechanical properties of electron spins, fish may have evolved a compass similar in its function to the technical devises developed by humans. How these mechanisms work precisely and how they are integrated are research questions addressed in SFB 1372.

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