The magnetic cycle of the Sun in the spectral region

1999 ◽  
Vol 18 (1) ◽  
pp. 287-296
Author(s):  
Yu. R. Rivin
Keyword(s):  
Spectral Region ◽  
The Sun ◽  
Magnetic Cycle

A Clock in the Sun?

2019 ◽  
Vol 15 (S354) ◽  
pp. 127-133
Author(s):  
C. T. Russell ◽  
J. G. Luhmann ◽  
L. K. Jian
Keyword(s):  
Sunspot Number ◽  
Solar Minimum ◽  
Sunspot Cycle ◽  
Solar Dynamo ◽  
The Sun ◽  
Average Period ◽  
Magnetic Cycle ◽  
Number Cycle ◽  
As If

AbstractThe sunspot cycle is quite variable in duration and amplitude, yet in the long term, it seems to return to solar minimum on schedule, as if guided by a clock with an average period of close to 11.05 years for the sunspot number cycle and 22.1 years for the magnetic cycle. This paper provides a brief review of the sunspot number cycle since 1750, discusses some of the processes controlling the solar dynamo, and provides clues that may add to our understanding of what controls the cadence of the solar clock.

Coronal Large-Scale Structure in Odd and Even 11-Year Cycles

1994 ◽  
Vol 144 ◽  
pp. 96
Author(s):  
V. I. Makarov ◽  
V. P. Mikhailutsa ◽  
M. P. Fatianov ◽  
T. V. Stepanova
Keyword(s):  
Large Scale ◽  
Radial Direction ◽  
Solar Magnetic Field ◽  
Essential Difference ◽  
The Sun ◽  
High Latitudes ◽  
Solar Cycles ◽  
Magnetic Cycle ◽  
Solar Magnetic Cycle ◽  
Odd Cycles

AbstractObservations of 22 solar eclipses (1914-1991) have been processed. Radial deviations of streamers in the polar and equatorial zones of the Sun in odd and even solar cycles have been studied. An essential difference of the degree of non-radiality of coronal rays at the same latitudes in odd and even cycles has been found. Deviations from the radial direction of streamers are large in the polar zones in the epoch of the maxima of even cycles and in the equatorial zones at the minima of odd cycles. Deviations from radiality at high latitudes are observed mainly in the poleward direction. The results obtained are interpreted in terms of a new model of the cycle, in which the properties of the solar magnetic field depend on the phase of a 22-year solar magnetic cycle.

scholarly journals A new imminent grand minimum?

2011 ◽  
Vol 7 (S286) ◽  
pp. 414-417
Author(s):  
Rodolfo G. Cionco ◽  
Rosa H. Compagnucci
Keyword(s):  
Solar System ◽  
Three Dimensional ◽  
Maunder Minimum ◽  
Fundamental Result ◽  
The Sun ◽  
Magnetic Cycle ◽  
Dynamical Parameters ◽  
Dalton Minimum ◽  
Grand Minima

AbstractThe planetary hypothesis of solar cycle is an old idea by which the planetary gravity acting on the Sun might have a non-negligible effect on the solar magnetic cycle. The advance of this hypothesis is based on phenomenological correlations between dynamical parameters of the Sun's movement around the barycenter of the Solar System and sunspots time series. In addition, several authors have proposed, using different methodologies that the first Grand Minima (GM) event of the new millennium is coming or has already begun. We present new fully three dimensional N-body simulations of the solar inertial motion (SIM) around the barycentre of the solar system in order to perform a phenomenological comparison between relevant SIM dynamical parameters and the occurrences of the last GM events (i.e., Maunder and Dalton). Our fundamental result is that the Sun acceleration decomposed in a co-orbital reference system shows a very particular behaviour that is common to Maunder minimum, Dalton minimum and the maximum of cycle 22 (around 1990), before the present prolonged minimum. We discuss our results in terms of a dynamical characterization of GM with relation to Sun dynamics and possible implications for a new GM event.

scholarly journals ABSORPTION OF SUNLIGHT BY ATMOSPHERIC SODIUM

1957 ◽  
Vol 35 (8) ◽  
pp. 918-927 ◽  
Author(s):  
J. A. Scrimger ◽  
D. M. Hunten
Keyword(s):  
Spectral Region ◽  
Scattered Light ◽  
Stray Light ◽  
Low Density ◽  
The Sun ◽  
Sodium Vapor ◽  
Sodium Layer ◽  
Residual Intensity ◽  
Narrow Spectral Region ◽  
The Continuum

A photometer has been built which is sensitive to light only in a very narrow spectral region near the sodium D-lines. The light is scattered by sodium vapor at low density and the scattered light recorded by a photoelectric spectrometer. The latter resolves the two lines and allows the effect of stray light to be eliminated. With sunlight as the source, the radiation detected is at the bottom of the Fraunhofer lines and the residual intensity there may be measured. It is found that this intensity decreases slightly (relative to the continuum) as the sun approaches the horizon. This effect is attributed to atmospheric sodium; the amount found by this method agrees well with that deduced from twilight measurements. The thickness of the sodium layer in atoms/cm.2 varies between 3 and 9 × 109 in winter and is about 1 × 109 in April. The measurements also give the residual intensities of the Fraunhofer lines in the incident sunlight, averaged over the whole of the sun's disk. These are (5.90 ± 0.46)% for D1 and (5.06 ± 0.24)% for D2.

scholarly journals Identifications of Some Highly-Ionized Iron and Nickel Lines in the 200–400 Å Region of the Solar Spectrum

1972 ◽  
Vol 14 ◽  
pp. 665-665
Author(s):  
K. G. Widing ◽  
G. Sandlin ◽  
R. Cowan
Keyword(s):  
Spectral Region ◽  
Solar Spectrum ◽  
The Sun ◽  
Solar Observations ◽  
Type 3 ◽  
Combination Line

AbstractA number of previously unclassified multiplets of FeXIV, XIII, XII, and XI produced by transitions of the type 3s23pn–3s3pn+1 are identified in the XUV spectrum of the Sun. The iron lines account for most of the previously unidentified strong lines between 330 and 370 Å. Solar observations of especial value for the investigation of the 300–400 Å region were the slitless spectroheliograms of September 22, 1968 (Purcell and Tousey, 1969) and November 4, 1969 (Tousey, 1971) – on which the image of a flare was recorded.Other solar identifications in the same spectral region include the resonance lines of NiXVII and NiXVIII, and one 3p–3d multiplet of FeXIII. The solar blend at 417 Å involving the FeXV inter-combination line and SXIV is resolved.

A Behavioural Model of the Solar Magnetic Cycle

2017 ◽  
Vol 13 (S335) ◽  
pp. 94-97
Author(s):  
Milton Munroe
Keyword(s):  
Magnetic Field ◽  
Conceptual Model ◽  
Differential Rotation ◽  
Toroidal Field ◽  
Solar Dynamo ◽  
The Sun ◽  
Poloidal Field ◽  
Magnetic Cycle ◽  
Poloidal Magnetic Field ◽  
Solar Magnetic Cycle

All recent models of solar magnetic cycle behaviour assume that the Ω-effect stretches an existing poloidal magnetic field into a toroidal field using differential rotation (Featherstone and Miesch 2015). The α-effect recycles the toroidal field back to a poloidal field by convection and rotation and this is repeated throughout the cycle. Computer simulations based on that conceptual model still leave many questions unanswered. It has not resolved where the solar dynamo is located, what it is or what causes the differential rotation which it takes for granted. Does this paradigm need changing? The conceptual model presented here examines the sun in horizontal sections, analyses its internal structure, presents new characterizations for the solar wind and structures found and shows how their interaction creates rotation, differential rotation, the solar dynamo and the magnetic cycle.

On the Origin of the Double Magnetic Cycle of the Sun

2008 ◽  
Vol 683 (1) ◽  
pp. 536-541 ◽  
Author(s):  
A. Vecchio ◽  
V. Carbone
Keyword(s):  
The Sun ◽  
Magnetic Cycle

scholarly journals Variation of Even and Odd Parity in the Solar Dynamo

1990 ◽  
Vol 138 ◽  
pp. 379-382
Author(s):  
A. Brandenburg ◽  
R. Meinel ◽  
D. Moss ◽  
I. Tuominen
Keyword(s):  
Phase Space ◽  
Time Scale ◽  
Beat Frequency ◽  
The Sun ◽  
Magnetic Cycle ◽  
Secular Variations ◽  
Spot Number ◽  
Term Variation ◽  
Long Time

We have studied axisymmetric nonlinear αω-dynamo models taking the interaction between even and odd parities fully into account. It turns out that the dominating type of symmetry is not always determined uniquely, but it can vary on a very long time scale compared to the period of the magnetic cycle. In some cases the frequency of this long term variation is close to the beat frequency of the two solutions with purely dipolar and purely quadrupolar parity. The occurrence of a second frequency is typical of solutions whose trajectory describes a torus in the phase space. We argue that this finding is of relevance for understanding secular variations observed in the Sun. For example measurements of sunspots indicate that the spot number on the northern hemisphere at present exceeds the number on the southern hemisphere. The reverse seems to have been the case at the end of last century.

scholarly journals Impact of the solar magnetic cycle on a protoplanetary disk

2009 ◽  
Vol 5 (S264) ◽  
pp. 401-403
Author(s):  
Andrey G. Tlatov
Keyword(s):  
Magnetic Field ◽  
Solar System ◽  
Protoplanetary Disk ◽  
The Sun ◽  
Keplerian Orbit ◽  
Magnetic Cycle ◽  
Periodic Magnetic Field ◽  
Solar Magnetic Cycle

AbstractWe consider the influence of the periodic magnetic field of the Sun on the protoplanetary disk. Solar magnetic cycle may create a special orbit, which were formed main planets of the solar system. In orbits on which magnetic field accumulation occurs most effectively, there is a substance replacement. The Keplerian orbit with the period close to the period of solar magnetic cycle T ~ TM is most unstable for material accumulation. Two most close orbits where there is an accumulation of substance have periods T = 1/2TM and T=5/4TM. These orbits on are close to orbits of Jupiter and Saturn. Other planets were probably formed under influence of gravitation of Jupiter, Saturn and solar magnetic cycle. Perhaps, the effect of periodic magnetic field can explain the Titius-Bode rule.

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