scholarly journals The reversal of the Sun’s magnetic field in cycle 24

2016 ◽  
Vol 2 (1) ◽  
pp. 3-18 ◽  
Author(s):  
Александр Мордвинов ◽  
Aleksandr Mordvinov ◽  
Алексей Певцов ◽  
Aleksey Pevtsov ◽  
Лука Бертелло ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Classical Model ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Opposite Polarity ◽  
Polar Field ◽  
Surface Magnetic Field ◽  
Current Cycle ◽  
Polar Magnetic Fields ◽  
Cycle 24

Analysis of synoptic data from the Vector Spectromagnetograph (VSM) of the Synoptic Optical Long-term Investigations of the Sun (SOLIS) and the NASA/NSO Spectromagnetograph (SPM) at the NSO/Kitt Peak Vacuum Telescope facility shows that the reversals of solar polar magnetic fields exhibit elements of a stochastic process, which may include the development of specific patterns of emerging magnetic flux, and the asymmetry in activity between Northern and Southern hemispheres. The presence of such irregularities makes the modeling and prediction of polar field reversals extremely hard if possible. In a classical model of solar activity cycle, the unipolar magnetic regions (UMRs) of predominantly following polarity fields are transported polewards due to meridional flows and diffusion. The UMRs gradually cancel out the polar magnetic field of the previous cycle, and rebuild the polar field of opposite polarity setting the stage for the next cycle. We show, however, that this deterministic picture can be easily altered by the developing of a strong center of activity, or by the emergence of an extremely large active region, or by a ‘strategically placed’ coronal hole. We demonstrate that the activity occurring during the current cycle 24 may be the result of this randomness in the evolution of the solar surface magnetic field.

scholarly journals The reversal of the Sun’s magnetic field in cycle 24

2016 ◽  
Vol 2 (1) ◽  
pp. 3-13 ◽  
Author(s):  
Александр Мордвинов ◽  
Aleksandr Mordvinov ◽  
Алексей Певцов ◽  
Aleksey Pevtsov ◽  
Лука Бертелло ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Classical Model ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Opposite Polarity ◽  
Polar Field ◽  
Surface Magnetic Field ◽  
Current Cycle ◽  
Polar Magnetic Fields ◽  
Cycle 24

Analysis of synoptic data from the Vector Spectromagnetograph (VSM) of the Synoptic Optical Long-term Investigations of the Sun (SOLIS) and the NASA/NSO Spectromagnetograph (SPM) at the NSO/Kitt Peak Vacuum Telescope facility shows that the reversals of solar polar magnetic fields exhibit ele-ments of a stochastic process, which may include the development of specific patterns of emerging magnetic flux, and the asymmetry in activity between northern and southern hemispheres. The presence of such irregu-larities makes the modeling and prediction of polar field reversals extremely hard if possible. In a classical model of solar activity cycle, the unipolar magnetic regions (UMRs) of predominantly following polarity fields are transported polewards due to meridional flows and dif-fusion. The UMRs gradually cancel out the polar mag-netic field of the previous cycle, and rebuild the polar field of opposite polarity setting the stage for the next cycle. We show, however, that this deterministic picture can be easily altered by the developing of a strong cen-ter of activity, or by the emergence of an extremely large active region, or by a ‘strategically placed’ coronal hole. We demonstrate that the activity occurring during the current cycle 24 may be the result of this random-ness in the evolution of the solar surface magnetic field.

Solar Wind Magnetic Field Turbulence over the Solar Activity Cycle Inferred from Coronal Sounding Experiments with Helios Linear-Polarized Signals

2019 ◽  
Vol 63 (3) ◽  
pp. 174-181
Author(s):  
A. I. Efimov ◽  
L. A. Lukanina ◽  
I. V. Chashei ◽  
M. K. Bird ◽  
M. Pätzold
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Solar Activity ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Solar Wind Magnetic Field ◽  
Magnetic Field Turbulence

scholarly journals The Persistence of Apparent Non-Magnetostatic Equilibrium in NOAA 11035

2014 ◽  
Vol 10 (S305) ◽  
pp. 35-41
Author(s):  
Sarah A. Jaeggli
Keyword(s):  
Magnetic Field ◽  
Active Region ◽  
Strong Magnetic Field ◽  
Solar Atmosphere ◽  
Activity Cycle ◽  
Opposite Polarity ◽  
Unusual Feature ◽  
Complete Picture

AbstractNOAA 11035 was a highly sheared active region that appeared in December 2009 early in the new activity cycle. The leading polarity sunspot developed a highly unusual feature in its penumbra, an opposite polarity pore with a strong magnetic field in excess of 3500 G along one edge, which persisted for several days during the evolution of the region. This region was well observed by both space- and ground-based observatories, including Hinode, FIRS, TRACE, and SOHO. These observations, which span wavelength and atmospheric regimes, provide a complete picture of this unusual feature which may constitute a force-free magnetic field in the photosphere which is produced by the reconnection of magnetic loops low in the solar atmosphere.

Diagnostic Tools for Sunspots: the Molecules C2, Mg H and Ti O

1994 ◽  
Vol 154 ◽  
pp. 489-492
Author(s):  
K Sinha
Keyword(s):  
Magnetic Field ◽  
Solar Activity ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Diagnostic Tools ◽  
Present Communication ◽  
Quiet Sun ◽  
Molecular Lines ◽  
Field Strengths

The aim of the present communication is to draw attention to the value of simultaneous observations of sunspot umbrae and the quiet Sun in selected molecular lines. It is felt that such observations may lead to an array of sunspot models which account for sunspot sizes, magnetic field strengths, and the solar activity cycle.

Geoeffectiveness of the ‘Battle of Grunwald day’ in 2012

2020 ◽  
Author(s):  
Agnieszka Gil ◽  
Renata Modzelewska ◽  
Szczepan Moskwa ◽  
Agnieszka Siluszyk ◽  
Marek Siluszyk ◽  
...  
Keyword(s):  
Geomagnetic Storm ◽  
Transmission Lines ◽  
Geomagnetic Storms ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Solar Origin ◽  
Electric Transmission Lines ◽  
Cycle 24 ◽  
Ap Index ◽  
Halo Coronal Mass Ejection

<p>During the solar activity cycle 24, which started at the end of 2008, Sun was behaving silently and there were not many spectacular geoeffective events. Here we analyze the geomagnetic storm which happened on July 15 of 2012 in the 602 anniversary of the famous Polish Battle of Grunwald. According to the NOAA scale, it was G3 geomagnetic storm with Bz heliospheric magnetic field component dropping up to -20 nT, Dst index below -130 nT, AE index greater than 1300 nT and ap index being above 130 nT. It was proceeded by the solar flare of X1.4 class on 12 of July. This geomagnetic storm was accompanied by the fast halo coronal mass ejection 16:48:05 on 12 of July-the first C2 appearance, with the apparent speed 885 km/s and space speed 1405 km/s. This geomagnetic storm was classified as the fourth of the strongest geomagnetic storms from SC 24. Around that time in Polish electric transmission lines infrastructure, there was observed a significant growth of the number of failures that might be of solar origin.</p><p><em>Acknowledgments: the Polish National Science Centre, grant number 2016/22/E/HS5/00406.</em></p>

scholarly journals Forecasting the peak of the present solar activity cycle 24

2018 ◽  
Vol 7 (1) ◽  
pp. 15-19 ◽  
Author(s):  
R.H. Hamid ◽  
B.A. Marzouk
Keyword(s):  
Solar Activity ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Cycle 24

scholarly journals The Behaviour of Galactic Cosmic-Ray Intensity During Solar Activity Cycle 24

Solar Physics ◽  
2019 ◽  
Vol 294 (1) ◽  
Author(s):  
Eddie Ross ◽  
William J. Chaplin
Keyword(s):  
Solar Activity ◽  
Cosmic Ray ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Cosmic Ray Intensity ◽  
Cycle 24 ◽  
Galactic Cosmic Ray

Automatic detection of magnetopause and bow shock crossing signatures in MESSENGER magnetometer data using Convolutional Neural Networks.

2021 ◽  
Author(s):  
Alexander Lavrukhin ◽  
David Parunakian ◽  
Dmitry Nevskiy ◽  
Sahib Julka ◽  
Michael Granitzer ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Three Dimensional ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Bow Shock ◽  
Cycle Phase ◽  
Small Subset ◽  
Magnetometer Data ◽  
Spacecraft Mission ◽  
Planetary Magnetic Field

<p>During its 2011-2015 lifetime the MESSENGER spacecraft completed more than 4000 orbits around Mercury, producing vast amounts of information regarding the planetary magnetic field and magnetospheric processes. During each orbit the spacecraft left and re-entered the Hermean magnetosphere, giving us information about more than 8000 crossings of the bow shock and the magnetopause of Mercury's magnetosphere. The information obtained from the magnetometer data offers the possibility to study in depth the structures of the bow shock and magnetopause current sheets and their shapes. In this work, we take a step in this direction by automatically detecting the crossings of bow-shock and magnetopause. To this end, we propose a five-class problem and train a Convolutional Neural Network based classifier using the magnetometer data. Our key experimental results indicate that an average precision and recall of at least 87% and 96% can be achieved on the bow hock and magnetopause crossings by using only a small subset of the data. We also model the average three-dimensional shape of these boundaries depending on the external interplanetary magnetic field . Furthermore, we attempt to clarify the dependence of the two boundary locations on the heliocentric distance of Mercury and on the solar activity cycle phase. This work may be of particular interest for future Mercury research related to the BepiColombo spacecraft mission, which will enter Mercury’s orbit around December 2025.</p>

Magnetic Field of Sunspots During the Rising Phase of Activity Cycle 24

Astrophysics ◽  
2017 ◽  
Vol 60 (1) ◽  
pp. 90-99 ◽  
Author(s):  
O. S. Gopasyuk
Keyword(s):  
Magnetic Field ◽  
Activity Cycle ◽  
Cycle 24
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