The magnetic Sun

2008 ◽  
Vol 366 (1871) ◽  
pp. 1735-1748 ◽  
Author(s):  
Richard A Harrison
Keyword(s):  
Magnetic Fields ◽  
Stellar Atmospheres ◽  
Magnetic Star ◽  
The Sun ◽  
Basic Principles ◽  
Fundamental Nature ◽  
James Clerk Maxwell ◽  
The Earth ◽  
Basic Equations ◽  
The Way

The nature of our star, the Sun, is dominated by its complex and variable magnetic fields. It is the purpose of this paper to review the fundamental nature of our magnetic Sun by outlining the most basic principles behind the way the Sun works and how its fields are generated, and to examine not only the historical observations of our magnetic star, but, in particular, to study the wonderful observations of the Sun being made from space today. However, lying behind all of this are the most basic equations derived by James Clerk Maxwell, describing how the magnetic fields and plasmas of our Sun's atmosphere, and indeed of all stellar atmospheres, work and how they influence the Earth.

Geology Emerges as a Science

2021 ◽  
pp. 6-33
Author(s):  
Elisabeth Ervin-Blankenheim
Keyword(s):  
Twentieth Century ◽  
Sixteenth Century ◽  
Da Vinci ◽  
Leonardo Da Vinci ◽  
Basic Principles ◽  
Charles Lyell ◽  
The Earth ◽  
Forms Of Life ◽  
Principles Of Geology ◽  
The Way

This chapter and the next one cover the way in which geology came to be a science in its own right, spanning the early centuries of geology. Lives of crucial individual scientists from the sixteenth century to the beginning of the twentieth century are discussed by relating the stories and discoveries of each, commencing with Leonardo da Vinci and continuing with the European geologists, including Nicholaus Steno, Abraham Werner, James Hutton, Charles Lyell, and early fossilists such as Etheldred Benet. Steno, Werner, Hutton and Lyell, and other early geologists revealed and wrote about the basic principles of geology, painstakingly untangling and piecing together the threads of the Earth’s vast history. They made sense of jumbled sequences of rocks, which had undergone dramatic changes since they were formed, and discerned the significance of fossils, found in environments seemingly incongruous to where the creatures once lived, as ancient forms of life. They set the stage for further research on the nature of the Earth and life on it, providing subsequent generations of geologists and those who study the Earth the basis on which to refine and flesh out the biography of the Earth.

Variations of the magnetic fields of the sun and the earth in 7?50 day periods

Solar Physics ◽  
1994 ◽  
Vol 152 (1) ◽  
pp. 291-296 ◽  
Author(s):  
V. P. Bobova ◽  
N. N. Stepanian
Keyword(s):  
Magnetic Fields ◽  
The Sun ◽  
The Earth

Periodic imbalances of kinetic and magnetic energies in rotating magnetohydrodynamic turbulent flows

2020 ◽  
Author(s):  
Rustem Sirazov ◽  
Arakel Petrosyan
Keyword(s):  
Magnetic Fields ◽  
Temporal Dynamics ◽  
Wave Packets ◽  
Homogeneous Turbulence ◽  
Initial Time ◽  
The Sun ◽  
Magnetohydrodynamic Turbulence ◽  
The Earth ◽  
Magnetohydrodynamic Flows ◽  
N Wave

<p>A significant number of observed flows in geophysics, astrophysics, and laboratory experiments are in a state of magnetohydrodynamic turbulence. Among them are flows in the Earth’s outer core, in plasma shells of Earth, planets, and satellites of the solar system with strong magnetic fields, as well as flows in the Sun, stars, and astrophysical disks. Despite significant advances in the study of turbulence under the conditions typical of thermonuclear fusion devices, studies of the fundamental properties of homogeneous turbulence in rotating magnetohydrodynamic flows are still fragmentary and mainly concern turbulence in astrophysical disks, the solar tachocline and convective region of the Sun, and two-dimensional magnetohydrodynamic flows on the β-plane. Only in a few exceptional works were the properties of magnetohydrodynamic turbulence studied by simple analytical methods using Fourier series for similarity parameters, characteristic of the Earth’s core.</p><p>The aim of this work is to study the influence of the interaction of Alfvén wave packets on the dynamics of homogeneous turbulence. The method of calculation o magnetohydrodynamic turbulence we developed allows numerical simulation at large characteristic times and large external magnetic fields. The proposed method of setting the initial conditions for the velocity field makes it possible to satisfy the divergence-free, homogeneity, and turbulence isotropy conditions, as well as to set an arbitrary spectral distribution of the energy at the initial time without additional calculations. Numerical experiments demonstrate a nontrivial behavior of turbulent kinetic and magnetic energies. It is shown that periodic imbalance in energies occurs in the system in the form of conversion of kinetic energy into magnetic energy and vice versa. The analysis of the results shows that the detected nontrivial temporal dynamics of turbulence is caused by the periodic collisions of Alfvén wave packets.</p><p>This work was supported by the Russian Foundation for Basic Research (project no. 19-02-00016).</p>

scholarly journals Is There an Oblique Magnetic Rotator Inside the Sun?

1983 ◽  
Vol 66 ◽  
pp. 235-235
Author(s):  
G.R. Isaak
Keyword(s):  
Magnetic Fields ◽  
Convection Zone ◽  
Detailed Account ◽  
The Sun ◽  
Magnetic Perturbation ◽  
The Earth ◽  
Solar Oblateness

AbstractThe size of the rotational splitting recently observed (Claverie et al., 1981) is correlated with the 12.2d variation in the measurements of solar oblateness observed by Dicke (1976) and implies a convection zone of depth of 0.1 Rʘ. The near equality of amplitudes of global velocity oscillations (Claverie et al, 1981) of the various m components of the l = 1 and l = 2 modes as seen from the Earth viewing the Sun nearly along the equator is unexpected for pure rotational splitting. It is suggested that a magnetic perturbation is present and an oblique asymmetric magnetic rotator with magnetic fields of a few million gauss is responsible. A more detailed account was submitted to Nature.

Was Galileo Right and the Catholic Church Wrong?

2021 ◽  
pp. 36-49
Author(s):  
Steven L. Goldman
Keyword(s):  
Catholic Church ◽  
Scientific Method ◽  
Deductive Reasoning ◽  
Modern Science ◽  
The Sun ◽  
Natural Phenomena ◽  
The Earth ◽  
The Way ◽  
The Catholic Church

Galileo is an iconic founder of modern science, but his career and his contributions were far more complex than his reputation. He, too, championed a scientific method, but his thinking differed greatly from Bacon’s and Descartes’. Galileo’s method was based on Archimedes’ combination of experiment, mathematics, and deduction. This method allowed Galileo to claim certain knowledge of reality derived from mathematical accounts of natural phenomena. But he also claimed certain knowledge of reality derived directly from observation, as in his assertion that the Earth moved around the sun. While Galileo’s predictions were sometimes correct, he had no criterion for distinguishing between correct and incorrect inferences or for connecting his mathematical deductive reasoning about phenomena to the way they really were.

scholarly journals The magnetic field of the nearest cool star A Paradigm for Stellar Activity

1996 ◽  
Vol 176 ◽  
pp. 1-16
Author(s):  
Carolus J. Schrijver
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Differential Rotation ◽  
Stellar Atmospheres ◽  
The Sun ◽  
Flux Tubes ◽  
Cool Star ◽  
Temperature Regimes ◽  
The Magnetic Field ◽  
Selection Of

Looking at the Sun forges the framework within which we try to interpret stellar observations. The stellar counterparts of spots, plages, flux tubes, chromospheres, coronae, etc., are readily invoked when attempting to interpret stellar data. This review discusses a selection of solar phenomena that are crucial to understand stellar atmospheric activity. Topics include the interaction of magnetic fields and flows, the relationships between fluxes from different temperature regimes in stellar atmospheres, the photospheric flux budget and its impact on the measurement of the dynamo strength, and the measurement of stellar differential rotation.

The interconnection of the magnetic fields of the Earth and the Sun

Endeavour ◽  
1991 ◽  
Vol 15 (3) ◽  
pp. 126-132
Author(s):  
Michael Lockwood
Keyword(s):  
Magnetic Fields ◽  
The Sun ◽  
The Earth

Prologue

2016 ◽  
pp. 1-2
Author(s):  
Owen Gingerich
Keyword(s):  
Solar System ◽  
School Children ◽  
The Sun ◽  
The Earth ◽  
System P ◽  
Nicolaus Copernicus ◽  
The Way

In or around 1510 Nicolaus Copernicus, one of the sixteen directors of the northernmost Catholic diocese in Poland, invented the solar system. Wait a minute! you say. Wasn’t the sun always in the middle of the planets? But that wasn’t the way everyone else thought about it. Farmers, professors, priests, and school children all assumed the earth was solidly fixed in the middle of the cosmos. Every day the sun and stars revolved around the earth. The sun also moved, more slowly, in a path against the more distant stars so that it was higher in the sky in the summer and much lower in winter....

Geophysics: A Very Short Introduction

2018 ◽  
Author(s):  
William Lowrie
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Plate Tectonics ◽  
Seismic Waves ◽  
Outer Space ◽  
The Sun ◽  
Short Introduction ◽  
The Earth ◽  
Gravity And Magnetic ◽  
Harmful Radiation

Geophysics is the physics of the Earth. It encompasses areas such as seismology, plate tectonics, gravity, and the Earth’s magnetic field, all of which give clues to both the structure and the working of the Earth. Geophysics: A Very Short Introduction describes the internal and external processes that affect the planet, as well as the techniques used by geophysicists to investigate them. It explains how analysis of the seismic waves produced in earthquakes reveals the Earth’s internal structure, and tells how heat is transported through its interior. Chapters describe how satellite missions measure the gravity and magnetic fields, and explain how its magnetic field shields the Earth against harmful radiation from the Sun and outer space.

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