Meridional drift in the large-scale solar magnetic field pattern

AbstractThe almost stately evolution of the global heliospheric magnetic field pattern during most of the solar cycle belies the intense dynamic interplay of photospheric and coronal flux concentrations on scales both large and small. The statistical characteristics of emerging bipoles and active regions lead to development of systematic magnetic patterns. Diffusion and flows impel features to interact constructively and destructively, and on longer time scales they may help drive the creation of new flux. Peculiar properties of the components in each solar cycle determine the specific details and provide additional clues about their sources. The interactions of complex developing features with the existing global magnetic environment drive impulsive events on all scales. Predominantly new-polarity surges originating in active regions at low latitudes can reach the poles in a year or two. Coronal holes and polar caps composed of short-lived, small-scale magnetic elements can persist for months and years. Advanced models coupled with comprehensive measurements of the visible solar surface, as well as the interior, corona, and heliosphere promise to revolutionize our understanding of the hierarchy we call the solar magnetic field.

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Intersector disbalance of the large-scale open solar magnetic field fluxes, active and passive boundaries, and solar-terrestrial extrastorms

Geomagnetism and Aeronomy ◽

10.1134/s0016793208050034 ◽

2008 ◽

Vol 48 (5) ◽

pp. 578-594 ◽

Cited By ~ 2

Author(s):

K. G. Ivanov ◽

A. F. Kharshiladze

Keyword(s):

Magnetic Field ◽

Large Scale ◽

Solar Magnetic Field

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A Turbulent Heliosheath Driven by Rayleigh Taylor Instability

10.21203/rs.3.rs-198925/v1 ◽

2021 ◽

Author(s):

Merav Opher ◽

James Drake ◽

Gary Zank ◽

Gabor Toth ◽

Erick Powell ◽

...

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Large Scale ◽

Neutral Atom ◽

Solar Magnetic Field ◽

Characteristic Time Scale ◽

Rayleigh Taylor Instability ◽

Scale Turbulence ◽

Magnetohydrodynamic Simulations ◽

Rt Instability

Abstract The heliosphere is the bubble formed by the solar wind as it interacts with the interstellar medium (ISM). Studies show that the solar magnetic field funnels the heliosheath solar wind (the shocked solar wind at the edge of the heliosphere) into two jet-like structures1-2. Magnetohydrodynamic simulations show that these heliospheric jets become unstable as they move down the heliotail1,3 and drive large-scale turbulence. However, the mechanism that produces of this turbulence had not been identified. Here we show that the driver of the turbulence is the Rayleigh-Taylor (RT) instability caused by the interaction of neutral H atoms streaming from the ISM with the ionized matter in the heliosheath (HS). The drag between the neutral and ionized matter acts as an effective gravity which causes a RT instability to develop along the axis of the HS magnetic field. A density gradient exists perpendicular to this axis due to the confinement of the solar wind by the solar magnetic field. The characteristic time scale of the instability depends on the neutral H density in the ISM and for typical values the growth rate is ~ 3 years. The instability destroys the coherence of the heliospheric jets and magnetic reconnection ensues, allowing ISM material to penetrate the heliospheric tail. Signatures of this instability should be observable in Energetic Neutral Atom (ENA) maps from future missions such as IMAP4. The turbulence driven by the instability is macroscopic and potentially has important implications for particle acceleration.

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Time Evolution of the Large-Scale Solar Magnetic Field

Symposium - International Astronomical Union ◽

10.1017/s0074180900023056 ◽

1971 ◽

Vol 43 ◽

pp. 588-594 ◽

Cited By ~ 9

Author(s):

Martin D. Altschuler ◽

Gordon Newkirk ◽

Dorothy E. Trotter ◽

Robert Howard

Keyword(s):

Magnetic Field ◽

Time Evolution ◽

Large Scale ◽

Solar Magnetic Field ◽

Magnetic Polarity ◽

Zonal Harmonic ◽

The North

The six years of data from the Mt. Wilson Magnetic Atlas were analyzed in terms of surface harmonics. Between 1959 and 1962 the dominant harmonic corresponded to a dipole lying in the plane of the equator (2 sectors). There was also a significant zonal harmonic in which both solar poles had the same magnetic polarity, opposite to that at the equator. From the end of 1962 through 1964, the harmonic corresponding to 4 sectors was dominant. In 1965 and 1966, the harmonic of the north-south dipole became significant.

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Reconstruction of Sun-as-Star Magnetic Field Structure and Evolution Using Filament Observations

International Astronomical Union Colloquium ◽

10.1017/s0252921100048156 ◽

1998 ◽

Vol 167 ◽

pp. 493-496

Author(s):

Dmitri I. Ponyavin

Keyword(s):

Magnetic Field ◽

Solar Cycle ◽

Large Scale ◽

Solar Magnetic Field ◽

Close Association ◽

Field Structure ◽

The Sun ◽

Magnetic Field Structure ◽

Large Scale Magnetic Field ◽

Field Organization

AbstractA technique is used to restore the magnetic field of the Sun viewed as star from the filament distribution seen on Hα photographs. For this purpose synoptic charts of the large-scale magnetic field reconstructed by the McIntosh method have been compared with the Sun-asstar solar magnetic field observed at Stanford. We have established a close association between the Sun-as-star magnetic field and the mean magnetic field inferred from synoptic magnetic field maps. A filtering technique was applied to find correlations between the Sun-as-star and large-scale magnetic field distributions during the course of a solar cycle. The correlations found were then used to restore the Sun-as-star magnetic field and its evolution in the late 1950s and 1960s, when such measurements of the field were not being made. A stackplot display of the inferred data reveals large-scale magnetic field organization and evolution. Patterns of the Sun-as-star magnetic field during solar cycle 19 were obtained. The proposed technique can be useful for studying the solar magnetic field structure and evolution during times with no direct observations.

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Beyond sunspots: Studies using the McIntosh Archive of global solar magnetic field patterns

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317003726 ◽

2016 ◽

Vol 12 (S328) ◽

pp. 93-100 ◽

Cited By ~ 3

Author(s):

Sarah E. Gibson ◽

David Webb ◽

Ian M. Hewins ◽

Robert H. McFadden ◽

Barbara A. Emery ◽

...

Keyword(s):

Magnetic Field ◽

Large Scale ◽

Solar Magnetic Field ◽

Coronal Holes ◽

Magnetic Polarity ◽

Solar Cycles ◽

Polarity Inversion ◽

Magnetic Structures ◽

Field Patterns ◽

Global Evolution

AbstractIn 1964 (Solar Cycle 20; SC 20), Patrick McIntosh began creating hand-drawn synoptic maps of solar magnetic features, based on Hα images. These synoptic maps were unique in that they traced magnetic polarity inversion lines, and connected widely separated filaments, fibril patterns, and plage corridors to reveal the large-scale organization of the solar magnetic field. Coronal hole boundaries were later added to the maps, which were produced, more or less continuously, into 2009 (i.e., the start of SC 24). The result was a record of ~45 years (~570 Carrington rotations), or nearly four complete solar cycles of synoptic maps. We are currently scanning, digitizing and archiving these maps, with the final, searchable versions publicly available at NOAA's National Centers for Environmental Information. In this paper we present preliminary scientific studies using the archived maps from SC 23. We show the global evolution of closed magnetic structures (e.g., sunspots, plage, and filaments) in relation to open magnetic structures (e.g., coronal holes), and examine how both relate to the shifting patterns of large-scale positive and negative polarity regions.

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Rotation of Large Scale Patterns on the Solar Surface as Determined from Filament and Millimeter Data

International Astronomical Union Colloquium ◽

10.1017/s025292110007977x ◽

1991 ◽

Vol 130 ◽

pp. 279-281

Author(s):

S. Pohjolainen ◽

B. Vršnak ◽

H. Teräsranta ◽

S. Urpo ◽

R. Brajša ◽

...

Keyword(s):

Magnetic Field ◽

Low Temperature ◽

Large Scale ◽

Solar Magnetic Field ◽

Solar Surface ◽

Field Patterns

AbstractThe rotation of large scale solar magnetic field patterns was studied using quiescent filaments and low temperature regions observed at 37 GHz as tracers.

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Large Scale Solar Magnetic Fields: Temporal Variations

Symposium - International Astronomical Union ◽

10.1017/s0074180900182580 ◽

2004 ◽

Vol 219 ◽

pp. 552-556 ◽

Cited By ~ 4

Author(s):

R. Knaack ◽

J. O. Stenflo

Keyword(s):

Magnetic Field ◽

Time Series ◽

Large Scale ◽

Solar Magnetic Field ◽

Temporal Variations ◽

Solar Photosphere ◽

Solar Cycles ◽

Radial Magnetic Field ◽

Quasi Biennial Oscillation ◽

Harmonic Decomposition

We have investigated the temporal evolution of the solar magnetic field during solar cycles 20, 21 and 22 by means of spherical harmonic decomposition and subsequent time series analysis. A 33 yr and a 25 yr time series of daily magnetic maps of the solar photosphere, recorded at the Mt. Wilson and NSO/Kitt Peak observatories respectively, were used to calculate the spherical coefficients of the radial magnetic field. Fourier and wavelet analysis were then applied to deduce the temporal variations. We compare the results of the two datasets and present examples of zonal modes which show significant variations, e. g. with a period of approx. 2.0—2.5 years. We provide evidence that this quasi-biennial oscillation originates mainly from the southern hemisphere. Furthermore, we show that low degree modes with odd l — m exhibit periods of 29.2 and 28.1 days while modes with even l — m show a dominant period of 26.9 days. A resonant modal structure of the solar magnetic field (apart from the 22 yr cycle) has not been found.

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Sector Structure of the Solar Magnetic Field

Symposium - International Astronomical Union ◽

10.1017/s0074180900023202 ◽

1971 ◽

Vol 43 ◽

pp. 744-753 ◽

Cited By ~ 6

Author(s):

John M. Wilcox

Keyword(s):

Magnetic Field ◽

Large Scale ◽

Solar Magnetic Field ◽

Photospheric Magnetic Field ◽

The Other ◽

The Sun ◽

Sector Structure ◽

Sector Boundary ◽

The North

The solar sector structure consists of a boundary in the north-south direction such that on one side of the boundary the large-scale weak photospheric magnetic field is predominantly directed out of the Sun, and on the other side of the boundary this field is directed into the Sun. The region westward of a solar sector boundary tends to be unusually quiet and the region eastward of a solar sector boundary tends to be unusually active. This tendency is discussed in terms of flares, coronal enhancements, plage structure and geomagnetic response.

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