Eindimensionale Plasmaströmung in gekreuzten elektrischen und magnetischen Feldern

An investigation was made of a steady, one-dimensional plasma flow in crossed electric and magnetic fields. The interaction between the flow and the fields causes various flow types. In general, the flow is either supersonic or subsonic in the entire channel. Under certain circumstances, however, a transsonic flow may develop. Finally, flows exist with a steady shock front, the position and strength of which depend on the magnetic field strength and the pressure at the end of the tube.

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A portable apparatus for measuring the magnetic field strength in an electromagnetic wave

Mathematical Proceedings of the Cambridge Philosophical Society ◽

10.1017/s0305004100010069 ◽

1931 ◽

Vol 27 (3) ◽

pp. 481-489

Author(s):

L. G. Vedy ◽

A. F. Wilkins

Keyword(s):

Magnetic Field ◽

Electromagnetic Wave ◽

Magnetic Fields ◽

Field Strength ◽

Magnetic Field Strength ◽

Special Means ◽

Portable Apparatus ◽

The Magnetic Field ◽

Field Strengths

A portable apparatus is described which is capable of measuring directly, by means of a loop aerial, the magnetic field in an electromagnetic wave. Accurate measurements are possible of magnetic fields corresponding to field strengths of 0·2 millivolts per metre. Special means of providing small known calibrating E. M. F. S are described. The apparatus can be used to measure signals over the range 6 microvolts to 300 millivolts. Used in conjunction with a small portable vertical aerial, field strengths down to 2 microvolts per metre can be measured.

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The connection of fine-structure photospheric features in active regions with magnetic fields

Symposium - International Astronomical Union ◽

10.1017/s0074180900021513 ◽

1968 ◽

Vol 35 ◽

pp. 201-201

Author(s):

N. V. Steshenko

Keyword(s):

Magnetic Field ◽

Fine Structure ◽

High Resolution ◽

Magnetic Fields ◽

Field Strength ◽

Magnetic Field Strength ◽

Active Regions ◽

Transverse Magnetic ◽

List Type ◽

The Magnetic Field

1.The fine structure of the proton sunspot group of July 4–8, 1966 was studied on the basis of high-resolution heliograms. The comparison of the orientation between penumbral filaments and the transverse magnetic fields (observed by A.B. Severny and T.T. Tsap) shows that the direction of the filaments coincides in general with that of the magnetic field.2.Measurements of the magnetic fields of smallest pores (1·5″-2″) showed that the pores are always connected with strong magnetic field (in average 1400 gauss), which is localized at the same small area as the pore.3.Magnetic fields of faculae are concentrated in small elements with the dimension not exceeding 1·5″-3″. Magnetic-field strength H|| of about 45% of facular granules is within the limits of photographic measuring errors (approximately 25 gauss). For a quarter of all facular granules the strength H|| is from 25–50 gauss; about 30% of facular granules have H|| > 50 gauss, and sometimes there appear faculae with field strength of about 200 gauss. The magnetic-field strength of facular granules, which are found directly above spots, is 10–20 times less than the field strength of spots. This field is 80–210 gauss only.4.All observational data mentioned above show that the appearance of the fine-structure features in active regions is directly connected with the fine structure of magnetic field of different strength and different orientation. The study of high-resolution heliograms gives additional information about the fine structure of the magnetic field.

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On the magnetic-field configuration in sunspots

Symposium - International Astronomical Union ◽

10.1017/s0074180900021525 ◽

1968 ◽

Vol 35 ◽

pp. 202-210

Author(s):

O. Kjeldseth Moe

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Field Strength ◽

Magnetic Field Strength ◽

Solar Disk ◽

Field Configuration ◽

Solar Observatory ◽

Line Profiles ◽

Magnetic Field Configuration ◽

The Magnetic Field

During 1963–67 observations of the magnetic fields in sunspots have been obtained at the Oslo Solar Observatory. For the largest spots the detailed distribution of the magnetic-field strength is found. Based on calculations of line profiles made by the author (Kjeldseth Moe, 1967) also the direction of the magnetic field is derived. Observations of the magnetic field of the same spot at several positions on the solar disk give further information regarding the magnetic-field configuration. Our results are in fair agreement with those of Bumba (1962).

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Asymmetric reconnection at the bow shock

10.5194/egusphere-egu2020-4750 ◽

2020 ◽

Author(s):

Herbert Gunell ◽

Maria Hamrin ◽

Oleksandr Goncharov ◽

Alexandre De Spiegeleer ◽

Stephen Fuselier ◽

...

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Field Strength ◽

Magnetic Field Strength ◽

Plasma Flow ◽

Bow Shock ◽

The Other ◽

Magnetospheric Multiscale ◽

The Magnetic Field

<p>Can reconnection be triggered as a directional discontinuity (DD) crosses the bow shock? Here we present some unique observations of asymmetric reconnection at a quasi-perpendicular bow shock as an interplanetary DD is crossing it simultaneously with the Magnetospheric Multiscale (MMS) mission. The data show indications of ongoing reconnection at the bow shock southward of the spacecraft. The DD is also observed by several upstream spacecraft (ACE, WIND, Geotail, and THEMIS B) and one downstream in the magnetosheath (Cluster 4), but none of them resolve signatures of ongoing reconnection. We therefore suggest that reconnection was temporarily triggered as the DD was compressed by the shock. Bow shock reconnection is inevitably asymmetric with both the density and the magnetic field strength being higher on one side of the X-line (the magneosheath side) than on the other side where the plasma flow also is supersonic (the solar wind side). Asymmetric reconnection of the bow shock type has never been studied before, and the data discussed here are hence unique.</p>

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PENGARUH MEDAN MAGNET TERHADAP DIAMETER PERKECAMBAHAN KACANG HIJAU

Jurnal Fisika : Fisika Sains dan Aplikasinya ◽

10.35508/fisa.v5i1.2030 ◽

2020 ◽

Vol 5 (1) ◽

pp. 66-70

Author(s):

Aditya Vethra Prasetyo

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Field Strength ◽

Magnetic Field Strength ◽

Green Bean ◽

Green Beans ◽

Bean Sprout ◽

Randomized Design ◽

Completely Randomized Design ◽

The Magnetic Field

Abstrak Penelitian yang dilakukan berjudul “Pengaruh Medan Magnet Terhadap Diameter Perkecambahan Kacang Hijau”. Penelitian ini bertujuan untuk mengetahui pengaruh medan magnet terhadap diameter perkecambahan kacang hijau. Penelitian ini disusun dalam Rancangan Acak Lengkap (RAL) dengan satu faktor, yaitu kuat medan magnet dalam waktu yang sama yang terdiri dari kontrol (0 mT), 5,3 mT, 10,7 mT, 16,1 mT, 21,5 mT. Parameter yang diukur adalah diameter batang kecambah kacang hijau. Data dianalisis ragam dilanjutkan dengan uji DMRT pada taraf α = 5%. Hasil penelitian menunjukkan bahwa pemaparan medan magnet mempengaruhi diameter batang kecambah kacang hijau. Perlakuan yang menyebabkan perkembangan diameter batang terbesar adalah 21,5 mT. Kata kunci: kacang hijau, medan magnet, diameter Abstract The study was conducted entitled "The Effect of Magnetic Fields on the Diameter of Green Bean Germination". This study aims to determine the effect of the magnetic field on the diameter of green bean germination. This research was arranged in a Completely Randomized Design (CRD) with one factor, namely magnetic field strength at the same time consisting of controls (0 mT), 5.3 mT, 10.7 mT, 16.1 mT, 21.5 mT . The parameter measured is the diameter of the green bean sprout stem. Data were analyzed by continued variance with DMRT test at α = 5%. The results showed that exposure to the magnetic field affected the diameter of the green bean sprout stem. The treatment that caused the largest stem diameter development was 21.5 mT. Keywords: green beans, magnetic field, diameter

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Interaction of Interplanetary Shocks with the Moon

10.5194/egusphere-egu2020-5971 ◽

2020 ◽

Author(s):

Xiaoyan Zhou ◽

Nojan Omidi

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Field Strength ◽

Shock Front ◽

Magnetic Field Strength ◽

Interplanetary Shocks ◽

The Moon ◽

Energetic Ions ◽

The Core ◽

The Magnetic Field

<p>In this presentation, we use data from THEMIS-ARTEMIS spacecraft and electromagnetic hybrid (kinetic ions, fluid electrons) simulations to describe the nature of the interaction between interplanetary shocks and the Moon. In the absence of a global magnetic field and an ionosphere at the Moon, solar wind interaction is controlled by (1) absorption of the core solar wind protons on the dayside; (2) access of supra-thermal and energetic ions in the solar wind to the lunar tail; (3) penetration and passage of the IMF through the lunar body. This results in a lunar tail populated by energetic ions and enhanced magnetic field in the central tail region. In general, ARTEMIS observations show a clear jump in the magnetic field strength associated with the passage of the interplanetary shock regardless of the position in the tail. Compared to the shock front observed in the solar wind, the magnetic field strength in the tail is stronger both upstream and downstream of the shock which is consistent with the expectations of larger field strengths in the tail. In addition, the transition from upstream to downstream magnetic field strength takes longer time as compared to the solar wind, indicating the broadening in space of the shock transition region. In contrast, plasma observations show that depending on the position of the spacecraft in the tail, a density enhancement in association with the shock front may or may not be observed. Using the observed solar wind conditions, we have used hybrid simulations to examine the interaction of interplanetary shocks with the Moon. The results indicate that by virtue of IMF passage through the lunar body, the magnetic field shock front also passes through the Moon and as such a jump in the magnetic field strength is observed throughout the lunar tail in association with the passage of the shock. As expected, the field strength in the upstream and downstream regions in the tail are larger than the corresponding values in the solar wind. In addition, the passage of the shock through the lunar tail is associated with the broadening of the shock front. The absorption of the core solar wind protons on the dayside introduces a density hole in the shock front as it passes through the Moon and the lunar tail and, as such, the shock front as a whole is disrupted. This hole is gradually filled with the ambient plasma while it travels further down the tail until eventually the shock front is fully restored a few lunar radii away from the Moon. The simulation results are found to be consistent with ARTEMIS observations. Here we also discuss the impacts of shock Mach number on the interaction. These results depict the lunar environment under transient solar wind conditions, which provide helpful information for the NASA&#8217;s plan to return humans to the Moon.</p>

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On the Configuration of the Magnetic Field of β CrB

International Astronomical Union Colloquium ◽

10.1017/s0252921100080933 ◽

1976 ◽

Vol 32 ◽

pp. 613-622

Author(s):

I.A. Aslanov ◽

Yu.S. Rustamov

Keyword(s):

Magnetic Field ◽

Field Strength ◽

Radial Velocity ◽

Magnetic Field Strength ◽

Complex Shape ◽

Rotation Period ◽

Field Variation ◽

Magnetic Field Variation ◽

Secular Variations ◽

The Magnetic Field

SummaryMeasurements of the radial velocities and magnetic field strength of β CrB were carried out. It is shown that there is a variability with the rotation period different for various elements. The curve of the magnetic field variation measured from lines of 5 different elements: FeI, CrI, CrII, TiII, ScII and CaI has a complex shape specific for each element. This may be due to the presence of magnetic spots on the stellar surface. A comparison with the radial velocity curves suggests the presence of a least 4 spots of Ti and Cr coinciding with magnetic spots. A change of the magnetic field with optical depth is shown. The curve of the Heffvariation with the rotation period is given. A possibility of secular variations of the magnetic field is shown.

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The effects of magnetic field strength on the properties of wind generated from hot accretion flow

Astronomy and Astrophysics ◽

10.1051/0004-6361/201832985 ◽

2018 ◽

Vol 615 ◽

pp. A35 ◽

Cited By ~ 10

Author(s):

De-Fu Bu ◽

Amin Mosallanezhad

Keyword(s):

Magnetic Field ◽

Field Strength ◽

Pressure Gradient ◽

Magnetic Field Strength ◽

Magnetic Pressure ◽

Gas Pressure ◽

Accretion Flow ◽

Accretion Flows ◽

Black Hole Accretion ◽

The Magnetic Field

Context. Observations indicate that wind can be generated in hot accretion flow. Wind generated from weakly magnetized accretion flow has been studied. However, the properties of wind generated from strongly magnetized hot accretion flow have not been studied. Aims. In this paper, we study the properties of wind generated from both weakly and strongly magnetized accretion flow. We focus on how the magnetic field strength affects the wind properties. Methods. We solve steady-state two-dimensional magnetohydrodynamic equations of black hole accretion in the presence of a largescale magnetic field. We assume self-similarity in radial direction. The magnetic field is assumed to be evenly symmetric with the equatorial plane. Results. We find that wind exists in both weakly and strongly magnetized accretion flows. When the magnetic field is weak (magnetic pressure is more than two orders of magnitude smaller than gas pressure), wind is driven by gas pressure gradient and centrifugal forces. When the magnetic field is strong (magnetic pressure is slightly smaller than gas pressure), wind is driven by gas pressure gradient and magnetic pressure gradient forces. The power of wind in the strongly magnetized case is just slightly larger than that in the weakly magnetized case. The power of wind lies in a range PW ~ 10−4–10−3 Ṁinc2, with Ṁin and c being mass inflow rate and speed of light, respectively. The possible role of wind in active galactic nuclei feedback is briefly discussed.

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COMPARISON OF CARDIAC MAGNETIC FIELD DISTRIBUTIONS DURING DEPOLARIZATION AND REPOLARIZATION

International Journal of Bifurcation and Chaos ◽

10.1142/s0218127403008971 ◽

2003 ◽

Vol 13 (12) ◽

pp. 3783-3789 ◽

Cited By ~ 4

Author(s):

F. E. SMITH ◽

P. LANGLEY ◽

L. TRAHMS ◽

U. STEINHOFF ◽

J. P. BOURKE ◽

...

Keyword(s):

Magnetic Field ◽

Field Strength ◽

Magnetic Field Strength ◽

Field Distribution ◽

Normal Subjects ◽

The Body ◽

Magnetic Field Distribution ◽

T Wave ◽

High Magnetic Field Strength ◽

The Magnetic Field

Multichannel magnetocardiography measures the magnetic field distribution of the human heart noninvasively from many sites over the body surface. Multichannel magnetocardiogram (MCG) analysis enables regional temporal differences in the distribution of cardiac magnetic field strength during depolarization and repolarization to be identified, allowing estimation of the global and local inhomogeneity of the cardiac activation process. The aim of this study was to compare the spatial distribution of cardiac magnetic field strength during ventricular depolarization and repolarization in both normal subjects and patients with cardiac abnormalities, obtaining amplitude measurements by magnetocardiography. MCGs were recorded at 49 sites over the heart from three normal subjects and two patients with inverted T-wave conditions. The magnetic field intensity during depolarization and repolarization was measured automatically for each channel and displayed spatially as contour maps. A Pearson correlation was used to determine the spatial relationship between the variables. For normal subjects, magnetic field strength maps during depolarization (R-wave) showed two asymmetric regions of magnetic field strength with a high positive value in the lower half of the chest and a high negative value above this. The regions of high R-wave amplitude corresponded spatially to concentrated asymmetric regions of high magnetic field strength during repolarization (T-wave). Pearson-r correlation coefficients of 0.7 (p<0.01), 0.8 (p<0.01) and 0.9 (p<0.01) were obtained from this analysis for the three normal subjects. A negative correlation coefficient of -0.7 (p<0.01) was obtained for one of the subjects with inverted T-wave abnormalities, suggesting similar but inverted magnetic field and current distributions to normal subjects. Even with the high correlation values in these four subjects, the MCG was able to identify differences in the distribution of magnetic field strength, with a shift in the T-wave relative to the R-wave. The measurement of cardiac magnetic field distribution during depolarization and repolarization of normal subjects and patients with clinical abnormalities should enable the improvement of theoretical models for the explanation of the cardiac depolarization and repolarization processes.

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