scholarly journals Theory of the diurnal variation of the magnetic needle, illustrated by experiments

1833 ◽  
Vol 2 ◽  
pp. 321-323
Keyword(s):  
Diurnal Variation ◽  
Small Scale ◽  
The Sun ◽  
Partial Heating ◽  
Similar Idea ◽  
Magnetic Meridian ◽  
Magnetic Needle ◽  
Magnetic Phenomena

Mr. Christie having been led to doubt the validity of the explanation of the moving easterly variation adopted by Canton, but at the same time having observed that the changes in deviation and intensity appear always to have reference to the position of the sun with regard to the magnetic meridian, was led to connect these phenomena with Professor Seebeck’s discovery of thermo-magnetism, and Professor Cumming’s subsequent experiments; and to refer the phenomena of diurnal variation to the effect of partial heating, modified, perhaps, by that of rotation, and by peculiar influence in the sun’s rays. In support of this opinion, he cites passages from papers by Professor Cumming and Dr. Traill, whom a similar idea appears also to have impressed. But in place of looking to the stony strata, of which the earth’s surface consists, as the elements of the thermo-magnetic apparatus which this doctrine requires, the author regards them as rather consisting of the atmosphere and the surfaces of land and water with which it is in contact. Thermo-magnetic phenomena, he remarks, have hitherto only been observed in metallic combinations, but this may be owing merely to the small scale on which our experiments are conducted.

scholarly journals XXI. Theory of the diurnal variation of the magnetic needle, illustrated by experiments

1827 ◽  
Vol 117 ◽  
pp. 308-354 ◽  
Keyword(s):  
Diurnal Variation ◽  
Considerable Effect ◽  
Subsequent Paper ◽  
The Sun ◽  
Influence Of Temperature ◽  
Terrestrial Magnetism ◽  
The Subject ◽  
Magnetic Meridian ◽  
Magnetic Needle

In a Paper published in the Transactions for 1823, I stated my opinion, that the diurnal variation of the needle was probably due to the influence of temperature, but that the principle adopted by Canton would not account for the morning easterly variation. In a subsequent paper, I pointed out that the changes in direction and intensity appeared always to have a reference to the position of the sun with regard to the magnetic meridian ; the direction of the needle being undisturbed nearly at the time the sun passed that meridian; and the horizontal intensity being the least at the same time. Having taken this view of the subject previously to my being aware of Dr. Seebeck's discovery, that magnetical phenomena will arise from a disturbance in the equilibrium of temperature, my knowledge of that discovery and of subsequent experiments, particularly those of Professor Cumming, confirmed me in the opinion, that temperature must have a considerable effect in producing some of the phenomena of terrestrial magnetism, although I considered that this influence might be modified by the effects produced by rotation, or by peculiar influence in the sun's rays.

scholarly journals On the diurnal variation of the magnetic declination of St. Helena

1851 ◽  
Vol 5 ◽  
pp. 664-664
Keyword(s):  
Diurnal Variation ◽  
Northern Hemisphere ◽  
Opposite Direction ◽  
Diurnal Variations ◽  
The Sun ◽  
The Earth ◽  
Magnetic Declination ◽  
St Helena ◽  
Magnetic Needle

It has long been known that the diurnal variation of the magnetic needle is in an opposite direction in the southern, to what it is in the northern hemisphere; and it was therefore proposed as a pro­blem by Arago, Humboldt and others, to determine whether there exists any intermediate line of stations on the earth where those diurnal variations disappear. The results recorded in the present paper are founded on observations made at St. Helena during the five consecutive years, from 1841 to 1845 inclusive; and also on similar observations made at Singapore, in the years 1841 and 1842; and show that at these stations, which are intermediate between the northern and southern magnetic hemispheres, the diurnal variations still take place; but those peculiar to each hemisphere prevail at opposite seasons of the year, apparently in accordance with the position of the sun with relation to the earth’s equator.

scholarly journals On irregularities observed in the direction of the compass needles of H. M. S. Isabella and Alexander, in their late voyage of discovery, and caused by the attraction of the iron contained in the ships

1833 ◽  
Vol 2 ◽  
pp. 109-109
Keyword(s):  
Magnetic Meridian ◽  
Magnetic Needle ◽  
Made In

In this paper Captain Sabine shows in what respect the effects of local attraction in the above-mentioned ships were conformable to observations made in previous voyages; and how far the errors found to take place on different courses, and under different dips of the magnetic needle, corresponded with those rules for calculating corrections recommended by Captain Flinders, who found that in every ship a compass would differ very materially from itself on being removed from one place to another, and this was found to be the case in the Isabella and Alexander. As the ships ascended Davis’s Straits, the binnacle compasses, in consequence of their construction, became nearly useless; accordingly, a standard compass was placed in the Isabella exactly amidship between the main and mizen mast, on a stout cross-beam, about nine feet above the deck; and in the Alexander amidship, on a box of sand five or six feet above deck. Captain Sabine next describes the methods by which the points of no error in these compasses were determined, and which were not in either ship coincident with the magnetic meridian.

scholarly journals I.—Secular Earth-Creep

1909 ◽  
Vol 6 (4) ◽  
pp. 145-148 ◽  
Author(s):  
E. H. L. Schwarz
Keyword(s):  
South Africa ◽  
Diurnal Variation ◽  
Royal Society ◽  
The Sun ◽  
Special Design ◽  
Important Paper ◽  
Preliminary Results ◽  
Gravitational Pull ◽  
Set Up ◽  
Horizontal Pendulum

Dr. J. R. Sutton has recently read a most important paper to the Royal Society of South Africa on the diurnal variation of level at Kimberley. The paper gave the preliminary results of observations made during the course of three years upon the variation of the level of the ground as recorded by a large horizontal pendulum of a special design made for the author by the Cambridge Instrument Company. It appeared from the results that the movements in the surface of the ground, which set up corresponding movements in the pendulum, were very great. The maximum westerly elongation of the extremity of the pendulum occurred about 5.30 a.m., the maximum easterly about 4.15 p.m., the medium positions a little before 11 a.m. and 9.30 p.m. Geometrically these movements may be represented on the hypothesis that the hemisphere facing the sun bulges out, forming a sort of meniscus to the geosphere. The rise and fall of the surface of the ground which such a supposition would postulate is enormous, and the very magnitude has led Dr. Sutton to hesitate in giving the figures. There can, however, be very little doubt that some rise and fall in the earth's surface is occasioned by the sun's gravitational pull, although the present figures may have to be lessened by taking into consideration other causes which contribute to the disturbance of the pendulum.

scholarly journals What scatter-hoarding animals have taught us about small-scale navigation

2010 ◽  
Vol 365 (1542) ◽  
pp. 901-914 ◽  
Author(s):  
Kristy L. Gould ◽  
Debbie M. Kelly ◽  
Alan C. Kamil
Keyword(s):  
Future Research ◽  
Small Scale ◽  
The Sun ◽  
Scatter Hoarding ◽  
Geometric Properties ◽  
Cue Use ◽  
Unique System ◽  
Spatial Locations

Many animals use cues for small-scale navigation, including beacons, landmarks, compasses and geometric properties. Scatter-hoarding animals are a unique system to study small-scale navigation. They have to remember and relocate many individual spatial locations, be fairly accurate in their searching and have to remember these locations for long stretches of time. In this article, we review what is known about cue use in both scatter-hoarding birds and rodents. We discuss the importance of local versus global cues, the encoding of bearings and geometric rules, the use of external compasses such as the Sun and the influence of the shape of experimental enclosures in relocating caches or hidden food. Scatter-hoarding animals are highly flexible in how and what they encode. There also appear to be differences in what scatter-hoarding birds and rodents encode, as well as what scatter-hoarding animals in general encode compared with other animals. Areas for future research with scatter-hoarding animals are discussed in light of what is currently known.

scholarly journals How to make the Sun look less like the Sun and more like a star?

2016 ◽  
Vol 12 (S328) ◽  
pp. 237-239
Author(s):  
A. A. Vidotto
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Vector Fields ◽  
Radial Component ◽  
Field Vector ◽  
Small Scale ◽  
General Context ◽  
The Sun ◽  
Flux Transport ◽  
Large Scale Magnetic Field

AbstractSynoptic maps of the vector magnetic field have routinely been made available from stellar observations and recently have started to be obtained for the solar photospheric field. Although solar magnetic maps show a multitude of details, stellar maps are limited to imaging large-scale fields only. In spite of their lower resolution, magnetic field imaging of solar-type stars allow us to put the Sun in a much more general context. However, direct comparison between stellar and solar magnetic maps are hampered by their dramatic differences in resolution. Here, I present the results of a method to filter out the small-scale component of vector fields, in such a way that comparison between solar and stellar (large-scale) magnetic field vector maps can be directly made. This approach extends the technique widely used to decompose the radial component of the solar magnetic field to the azimuthal and meridional components as well, and is entirely consistent with the description adopted in several stellar studies. This method can also be used to confront synoptic maps synthesised in numerical simulations of dynamo and magnetic flux transport studies to those derived from stellar observations.

scholarly journals Small Scale Solar Magnetic Fields: Theory

1977 ◽  
Vol 4 (2) ◽  
pp. 241-250 ◽  
Author(s):  
N. O. Weiss
Keyword(s):  
Magnetic Fields ◽  
Field Strength ◽  
Solar Physics ◽  
Small Scale ◽  
The Sun ◽  
Solar Magnetic Fields ◽  
Solar Granulation ◽  
The Past ◽  
Maximum Field Strength ◽  
Maximum Field

One of the most exciting developments in solar physics over the past eight years has been the success of ground based observers in resolving features with a scale smaller than the solar granulation. In particular, they have demonstrated the existence of intense magnetic fields, with strengths of up to about 1600G. Harvey (1976) has just given an excellent summary of these results.In solar physics, theory generally follows observations. Inter-granular magnetic fields had indeed been expected but their magnitude came as a surprise. Some problems have been discussed in previous reviews (Schmidt, 1968, 1974; Weiss, 1969; Parker, 1976d; Stenflo, 1976) and the new observations have stimulated a flurry of theoretical papers. This review will be limited to the principal problems raised by these filamentary magnetic fields. I shall discuss the interaction of magnetic fields with convection in the sun and attempt to answer such questions as: what is the nature of the equilibrium in a flux tube? how are the fields contained? what determines their stability? how are such strong fields formed and maintained? and what limits the maximum field strength?

MHD and Ion Kinetic Waves in Field-aligned Flows Observed by Parker Solar Probe

2021 ◽  
Vol 922 (2) ◽  
pp. 188
Author(s):  
L.-L. Zhao ◽  
G. P. Zank ◽  
J. S. He ◽  
D. Telloni ◽  
L. Adhikari ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Whistler Wave ◽  
Spectral Energy ◽  
Small Scale ◽  
The Sun ◽  
Fast Mode ◽  
Magnetic Fluctuations ◽  
Background Magnetic Field ◽  
Ion Cyclotron

Abstract Parker Solar Probe (PSP) observed predominately Alfvénic fluctuations in the solar wind near the Sun where the magnetic field tends to be radially aligned. In this paper, two magnetic-field-aligned solar wind flow intervals during PSP’s first two orbits are analyzed. Observations of these intervals indicate strong signatures of parallel/antiparallel-propagating waves. We utilize multiple analysis techniques to extract the properties of the observed waves in both magnetohydrodynamic (MHD) and kinetic scales. At the MHD scale, outward-propagating Alfvén waves dominate both intervals, and outward-propagating fast magnetosonic waves present the second-largest contribution in the spectral energy density. At kinetic scales, we identify the circularly polarized plasma waves propagating near the proton gyrofrequency in both intervals. However, the sense of magnetic polarization in the spacecraft frame is observed to be opposite in the two intervals, although they both possess a sunward background magnetic field. The ion-scale plasma wave observed in the first interval can be either an inward-propagating ion cyclotron wave (ICW) or an outward-propagating fast-mode/whistler wave in the plasma frame, while in the second interval it can be explained as an outward ICW or inward fast-mode/whistler wave. The identification of the exact kinetic wave mode is more difficult to confirm owing to the limited plasma data resolution. The presence of ion-scale waves near the Sun suggests that ion cyclotron resonance may be one of the ubiquitous kinetic physical processes associated with small-scale magnetic fluctuations and kinetic instabilities in the inner heliosphere.

II. Spots and Intense Flux Tubes

1988 ◽  
Vol 20 (1) ◽  
pp. 58-63
Author(s):  
J.C. Henoux
Keyword(s):  
Magnetic Field ◽  
Solar Activity ◽  
High Resolution ◽  
Solar Magnetic Field ◽  
Solar Physics ◽  
Small Scale ◽  
The Sun ◽  
Flux Tubes ◽  
Flux Concentration ◽  
Scientific Meetings

The development of research on starspots, stellar activity, and the suspected relationship between coronal heating and magnetic field have reenforced the interest of the study of the solar magnetic field and the study of the associated thermodynamic structures. Several proceedings of scientific meetings appeared from 1984 to 1987 (Measurements of Solar Vector Magnetic Fields, 1985 (I); The Hydrodynamics of the Sun, 1984 (II); High Resolution in Solar Physics, 1985 (III); Theoritical Problems in High Resolution Solar Physics, 1985 (IV); Small Scale Magnetic Flux Concentration in the Solar Atmosphere, 1986 (V)). The finding that the solar irradiance in affected by solar activity has renewed interest in photometry of sunspots and faculae. Sunspots have been used for investigating solar differential and meridional motions. Some results are also found in Section III.

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